To be honest, I've had some success with dating sites (Plenty of Fish and OKCupid; both totally free). But yeah, I've been in the same boat, as far as having any kind of long relationship lasting over a month in...geez, has it been five years?
Anyway, there's that and there's also MeetUp.com, which is more for groups with similar interests to get together and have fun. I've gone to a number of them here in Toronto, including my personal favourite: board game meetups. Yeah, lame, I know.