My wife and I were there last September before our Alaskan Cruise so we ony were ther 2 days... Dont miss Stanley Park... best way to see it is rent a bike and follow the 'wall trail', it is certainly beautiful.. there is an aquarium in there, small but very nice...
Grouse Mountain has breathtaking views... and Granville Island is fun... didn't have time to go to Victoria which everyone raves about...
Have a very nice trip!
PD Be careful around Chinatown and areas nearby... some 'unsavory' characters roaming around... also if you rent a car dont leave things visible around Stanley Park since there have been reports of broken windows and stolen items... I guess this goes for everywhere but I thought you should know...