I'm living here at the moment and it is FAB!
Crystaltips is right - some things about Vancouver are a bit dated e.g the cinemas are really old and manky.
The downtown area (Robson street) is a real tourist trap and the food around there is awful. But I guess, like all tourist cities, you have to just reach out that wee bit further for the genuine article (West 4th Avenue in the Kitsilano area - also lots of young families live there so lots of kids in restaurants etc).
Granville Island is cool (big food market) and has its own kids toy market (v.v.vv. popular with the locals).
Capilano Suspension bridge costs a bomb and the Lynn Valley bridge 15 mins away is just as good and.....free!
All the beaches (1 on north shore; 4 around town) are lifeguarded in summer with designated swimming areas. You are not allowed booze on the beaches - the cops randomly stop cars and check. There are also 2 outdoor (chlorinated) pools (Kitsilano and Stanley park).
The cable car up Grouse mountain is well worth a visit. In summer they have a birds of prey show and a lumberjack show every hour. There is also a bear refuge (although the bears tend to snooze during the heat of the day).
Shopping is not as cheap as the US and the global brands (e.g. GAP) work out the same price as the UK, although you'll get the sales tax back, making it cheaper.
Granville Street - avoid the end nearest Granville Bridge as that's where all the cannabis and sex shops are.
Chinatown well worth a peek as it's huge and EVERYTHING is in Chinese.
I'm not a huge fan of Stanley park as it's very touristy, although the bit nearest English Bay is nice, with lots of kids stuff going on.
The biggest attraction with Canada is the outdoors - that's where all the emphasis goes for tourism. Most holidaymakers stay in town for 3-4 days, go whale watching on Vancouver Island for a couple of days, then head off up to the mountains for a weeks or so. Best time to catch the whales is May and September/October.
Contact me through MN if you want and I can post you loads of tourist bumpf. The guidebook called 'The Irreverent Guide to Vancouver' is also very good - has the most child-friendly hotels etc.