Vancouver on 4-Days:
1. Capilano Suspension Bridge and walk around Lynn Canyon in North Van (you can take seabus across harbor on transit pass, and then bus from there). Driving is nice too.
2. Romance in the air? Head to the top of Grouse Mountain. If you're a fitness freak, do the Grouse grind, if not, take the gondola. Either way, on a clear day, the view is stunning.
3. Agreed on Stanley Park--walk around the seawall, and then have lunch somewhere in Coal Harbour--there's a place right on the docks, but its name escapes me.
4. Check-out gas-town. The cobblestone roads and eclectic feel is really worth it.
5. Jericho Beach and the Kits area--also English Bay is great.
6. All the shopping you'll want can be done by walking west on Robson from Burrard st to Denman. Then walk back on the other side. Don't worry about your feet, because there's some really great (and cheap) foot massage places on the way.
7. Look for a place called Happa if you like Asian food--it's like a Japanese tapas bar. It's also on Robson.
8. The aquarium is awesome (Stanley Park). You can also feed bread to the swans near-by. Sounds really gay, but actually quite cool!
9. Try any of these finer-dining restaraunts for a great experience: Raincity Grill, Glowball, Gotham Steakhouse, Joe Fortes (seafood), Bluewater Cafe, but there's literally hundreds of great places to eat downtown.
10. 4-days? Forget Whistler. Not enough time.
11. If you have a car, take a drive down Marine Drive in West Van from the Lion's Gate Bridge all the way to Horseshoe Bay and have coffee or lunch, or whatever out there.
12. If you're into bars and nightlife, the Commodore is an institution for its live music. The Roxy is an older crowd, busy most nights.
There's so much more in Vancouver for you not on my list. Take a day to just explore. It's got a great vibe there, and you'll have an amazing time.
Vince.