I have also a 2005 Honda CR-V. The left low beam headlight has burned out four times since last August. After inspecting the electrical system, the only thing that the dealer gives me as an option is to use a Honda bulb instead of a third party bulb.
I found a possible cause at: http://www.hondacarforum.com/honda-technical/43236-honda-crv-headlight-problems.html
See sam2000pres, they cleaned corrosion from the dimmer switch.