It depends what you are looking for.
I go to Fitness World (usually the Davie/Howe one), which has it's pros and cons.
* you can go to any fitness world in the lower mainland, and there are three downtown.
* One of them is 24 hours (4 days a week) which has been quite convenient for me many times
* For the first two years, it's reasonable ($50 per month or so). After two years, it's disgustingly cheap ($25 a month for me)
* There are hot guys there to motivate you while you work out.
* There are many free classes
* It's extremely busy at most times I want to work out (either before 10AM, or between 5PM and 9PM). You basically have to wait at least 15 minutes to get on a tread mill during those hours, no matter what.
* I don't think that the personal trainers there are particularly bright or knowledgeable.
They are friendly though. Well, some of them sound like they know some of what they're doing, but some of the exercises they have people do make me seriously wonder.
* The staff basically ignores you unless you make yourself a problem for them.
The only other gym I would strongly recommend (except for the price) is the YWCA. The gym is top notch, and it's usually very quiet. It's also got a pool and a hot tub all included, plus lots of quiet rooms to do stretching in, when not being used for classes.
Hope that helps.