Seasons in the Park is a very nice restaurant - good food, ambiance and view. If you reserve an early dinner, show up well in advance and go for a stroll through the rock/flower garden at QE Park and a tour through the conservatory.
Seasons and the Teahouse used to be owned by the same firm, but I don't know if that's still the case. The Teahouse is still nice, but I think its not as good as it once was.
Five Sails is a very nice restaurant, but quite expensive and a little pretentious. The same can be said of "C" Restaurant at the north end of False Creek (great food, slightly pretentious).
Cardero's isn't too bad - excellent food and water views.
Cannery is good if you and your date both like seafood (limited non-seafood menu and almost nothing for vegetarians). Before they closed the access to waterfront road from Victoria Street (or whatever its called), it had the advantage that if the romance shrivelled over dinner and she walked out on you then it was a short drive to the track
If you want great food in a very small, intimate (hole in the wall) restaurant, there's a restaurant on Hastings Street just inside Burnaby. I ate there a year ago but can't remember the name right now. I read recently that the chef was just appointed to represent Canada in an international culinary competition - the only chef from Canada to be so honoured! Perhaps someone else here knows the name.