I LOVE desserts. Everytime I eat out, I must get dessert. Hell sometimes, I get dessert before the main course! or eat main course with dessert at the same time. For someone who loves dessert so much, it's kinda weird I hate strawberries and ice cream.. so I can't comment too much on the best ice cream place in Vancouver.. :( sorry, although I heard marble slab is good..
For cakes, there is true confections that sell delicious large slices of cake (although service can be slow for no reason) and sometimes each customer has to spend a minimum charge, only on busy nights I believe. There's also small cake shops that sell delicious beautiful intricate cakes for a hefty price. Even so, they are worth it because they are such gems. Try Ganache Patisserie, deliciousness! There's also cheesecake etc and the cupcake store downtown. Oh and Beard Papa for large soft cream puffs!
Asian cake shops are a bit more affordable.. there's always Maxims, T&T, Anna's Cake Shop, and etc. but I personally prefer La Patisserie on W 41 I believe. They have cakes with pomelo, mango, coconut, etc.. yumyumyum Japanese cheesecake at Chicco is also very soft and delicious, they also have other yummy desserts.
A really cheap bakery is Valley Bakery on Hastings St. They have a assortment of cakes, petit fours, pies, etc for cheap!!
For crepes, I love La Bretagne Creperie. Really good and quite a big portion too. Forget Cafe Crepe (unless you also want cheap drinks) and go here instead!! If you don't want the calories but still want your sweet fix, qoola is a good choice- selling natural yogurt with a ton of different toppings.
As for restaurants, for never fail desserts, I think Cactus Club is the way to go. Their samplers has delicious traditional chocolate cake, apple pie, and cheesecake. My 3 faves! Moxie's xang'o is also really really good. This is probably one of the only times I will recommend a chain restaurant for something (and they are also good for huge groups I guess).
I've been told that La Terrazza has a delicious filo patrsy dessert, so that's a good try :) Sweet Revenge has mouth watering desserts as well, although there is also a minimum charge there. Oh and I definitely recommend the panna cotta at Campagnolo. Wow.