Mike: They do look like a lot of fun, especially with that 9,000 RPM redline…although, I am partial to V8’s with low end torque…the main problem with the S2000 is that I live in a climate where a convertible is really best used as a second (summer) car, and my wife is not ready for us having 3 cars… 
Prelude or Integra.
To me a pure sports car is something like a Corvette or Viper. Most of the former are pretty pricy and all of the latter is pricy.
An older Corvette is a possibility. They’re not that bad to service and there are a jillion of them around with comparatively low mileage and decent pricing. The trick would be a careful inspection to make sure there is no fiberglass cracking and try to verify the miles were not put on there a 1/2 mile at a time (quarter mile down and a quarter mile back).
Sporty cars, as opposed to sports cars, might include the Miata, Mustang, etc. and there’s nothing wrong with either of those. I love the Mustang GTs but that V-8 bumps the price up a bit and those earlier Fox body versions are going up in value. The thing I like about the 5.0 Mustang GTs is that they flat run even in stock form, they’re simple to service, and there’s a mountain of aftermarket stuff out there to make them go from a hauler to a real hauler.
Aha! New requirements!
In my business (web programming), we call that “Scope Creep.”
No convertibles narrows it down a lot. I’m almost thinking BMW now. But those are expensive. I think you might want to consider the Scion, then, and look up “Toyota Racing Development” (TRD). That’s some pretty cool stuff.
Low end torque? V8? Still sounds like a school bus is in the cards for you!
And a farm tractor can tow a trailer full of hemis for breakfast… actually, so can the school bus… and then you can take it out on the track… like these guys do: http://www.youtube.com/watch?v=Fh7fQz4xzW4
In all seriousness, though, my family used to own a used mini school bus. It was one of the best vehicles we’ve ever had. Had room for my family (all six of us) and luggage, and boat, got about 20mpg, rarely ever broke down (only once… when the rear u-joint decided to fall apart… on the highway…) and cost only $900 to buy. Lasted for about 5 years - it was an 88, we got it in 98, sold it (for $300) in 03.
Well I’m going COMPLETELY DIFFERENT…
I’d find a 60’s Camaro/Firebird or Mustang. Get one where thr frame is in good shape. There are THOUSANDS of parts available for these cars. From stock to aftermarket-stock to complete upgrades. Very easy to work on (well until you have to replace the heating core on the Firebird or Camaro).
And you can probably take 80% of the car apart with a 1/2 or 9/16 wrench and a couple screwdrivers. Plenty of room to work on the engine. It’s the kind of vehicle you can work on for years as an on going hobby or get it the way you want it and keep it that way for years.
Another completely different idea. Before you added the low-end torque requirements, I was thinking a Kharman Ghia fit all of your criteria. Definitely easy to work on and there are definitely tons of parts avaliable for them and if you maintain them, they can be every bit as reliable as a modern car. So maybe the stock engine might be a little anemic, but there are TONS of aftermarket air-cooled VW performance parts out there and you can, with a modest investment, get one of these to a point in which it will toast most stock sports cars.
Although I agree that many new cars like the Toyota Celica, Honda S2000, and the Mazda Miata are a nice sporty cars, I think if you enjoy working on cars and want to be able to fix them, an older small sport car, like a Triumph or an Alpha Romero would make for a lot of fun. An older car will tend to be more affordable than most brand new cars.
Mike: The Scion does look like fun, but it’s not available to me unless I import it…BMW would be GREAT but yes, expensive and hard to service yourself I imagine.
procter: There’s no convincing me of the school bus! Although, those might be easy to add the water2gas device on and get some great mileage!! 
ok4450: The Mustang has always been up there in my books, but I worried about reliability…are they pretty decent if they weren’t abused? (I like that 1/2 mile at a time analogy!)
MikeInNH: Those 60’s Camaro’s/Firebird’s/Mustang’s would be great, the trick for me would be to find one that isn’t rusted out…which means I’d be going pretty far to get one. But still a good idea.
GreasyJack: The Kharman Ghia idea is interesting, not my style, but probably would be an interesting project car. Probably expensive now though? Same goes for Jeremy’s ideas.
Thanks again everyone!
What about an old Camaro? Would that be more your style?
Lotus Elise, can get them used at a reasonable price. Toyota Power plant, so should be reliable, don’t know for sure though. Can’t get much more sporting than that, all sorts of variations on speed too!
Or how about an old Porsche(not so much cheap parts though), e30 BMW 3-series, BMW 2002i, Mini Cooper (the “old” one), Toyota Supra (Twin turbo). Tons of small and fast (definition of sports car) older cars still out there. Cost goes up for less rust though, of course.
Consider a sports sedan or GT. I define a GT as roadster with a fixed top. Think Boxter:Kayman or Z4 Roadster:Z4 Coupe. Your list of GTs might include the Corvette, Kayman, Z4 coupe, SLK-series, Elise and Elan. Sport coupes include 3-series, 5-series, CLK-series, CTS, WRX, WRX STi, Lancer Evolution, GTO, G8-GT and a whole lot more that the rest of the gang will add to the list.
If you give us a price range and whether you want a new or used car, we can narrow the list.
The Corvette, GTO, and G8-GT probably fit best if you want an 8-cyl engine. They should be relatively easy to work on compared to the European examples.
I like those, not my favorite, but the tough thing would be convincing the wife…it was hard enough for her to warm up to my 85 Cutlass…
Don’t tempt me with the Lotus Elise or Exige…LOVE those cars…definitely one of my all time favorite true sports cars.
I’d love an old Porsche, but are they easy to work on?
I like the old Austin Mini’s too, I saw one with a 3.5 Rover V8 in it…now that looked like fun!
I guess something older, easy to work on will be the best option…finding one without rust will be the tough part…and not flogged to death.
MikeInNH: Those 60’s Camaro’s/Firebird’s/Mustang’s would be great, the trick for me would be to find one that isn’t rusted out…which means I’d be going pretty far to get one. But still a good idea.
The main thing you have to worry about is the frame. Body parts are PLENTY…Most aftermarket. You can COMPLETELY UPGRADE the suspension and braking system to modern. I once removed the carb and installed a aftermarket Holly Fuel-Injection system.
And even if the Frame is bad…It can replaced with a NEW frame. There are companies that will make a new modern frame that’s even powercoated and MUCH STRONGER then origional.
As I said it’s one of those cars you can work on for years if you want to.
Say, Jad, where in Canada do you live? If you’re out west, I’d say the chances of finding an unrusted muscle car are pretty good. If you’re in Ontario or Quebec, or areas east, you’d be hard pressed to find anything over 15 years that isn’t all rusted.
That said, maybe consider some 80’s large sedans - Caddilacs, Caprices, or maybe a Monte Carlo. Also, you might have some luck looking for a 90’s Impala SS. Or, what about an old hearse. I think those would be cool!
Bummer. “Premium” small car? And here I thought all this time it was just an inexpensive fun economy car!
Ontario…so yeah, everything here rusts away pretty quick.
The Impala SS is a good suggestion though…those are rear wheel drive right?
The Fox body Mustangs are reliable and simple to service. The 5.0 engine is essentially the same engine as the smaller displacement 289 and the fact the engine has been around for so long says a lot about it’s reliability.
The 90s Impala SS is rear wheel drive and a pretty neat car IMHO. Would love to have one myself even if they are a larger 4 door car.
I agree that the old Camaros are reliable and simple to work on but there is one major problem. Price. Everybody in the world wants them and this drives the prices up. Ten years ago the second generation Camaros could be found for a reasonable price and now they’re going through the roof. Even the common 3rd generation (82-92) Camaros are on the way up; considerably it seems just in the last few years.
Another problem is that if you find one that needs a lot of trim pieces you will pay dearly. I have a '79 Z-28 project car (runs/drives well, looks slick) but needs the interior restored, one T-top, and T-tops seals. Year One is bordering on obscene in plastic prices (140 each on kick panels, 900 dollars for T-top seals and 2 grand for a pair of T-tops (Hurst version, not the OEM Fisher ones). You can see that this can add up to some serious bucks real quick. I’m still looking for a junker with a good, matching color interior and so far have not found it.
Most of these cars have been thrashed into the ground or converted into dirt track race cars with the interiors having been gutted and tossed. Dxxx it. 
Those Mustangs are a lot of fun…a buddy of mine in Detroit has owned a few and “upgraded” them…he took me out once in a heavily modified '89, I don’t think I’ve ever been in a car that accelerated that fast.
Are old Porsche’s or Jaguar’s easy to work on? Not cheap, I know…