It depends on what your preferences tend towards. I find if you're really looking for a dark tasting then go towards a French roast or Italian. The Americas tend to have a bit more aciidity/fruity flavor and can run the gamut from mild to a stronger flavor. I find that African beans tend to be among the better all around medium to strong flavor with a nice smooth finish. The roasting technique of the beans has a huge part in determining flavor. As to where. It still depends. Do you like regular drip style coffees or more the fancy lattes and cappucinos?
For latte's and cappucinos, one of the best barristas in Vancouver works at Cafe Artegiano (spelling!) downtown. He's placed very high in some weird world championship for these things. Otherwise, I find smaller places seem to make better lattes than Starbucks or Blenz. Personal favorites? Bean Around the World (different locations), Characters bookstore (they have a cafe inside), in Fort Langley there's an awesome bookstore/cafe right at the end of the street just before the Albion that does awesome desserts and good coffee; On West First ave Cypress (south east corner) the name I can't remember but there's always some real high end bikes (Ducati's) parked outside, Viva, near Cornwall and Arbutus' Joe's Cafe on Commercial Drive. I know there's actually tons more I've gone to for great latte's but I can't remember names and locations.
For drip coffees, stay away from Tim Horton's.
Granville Island has a place called Blue parrot, I think? Actually there's a couple of places in Granville Island Market that does good coffee, from Saltspring Island. I like Starbucks drip coffee and Blenz is okay. And as stupid as this sounds, Macdonald's isn't all that bad if you're desperate.