I was lucky enough to find a good shop in my area. They're a Trek shop, with plenty of the high performance bikes and stupid racing posters on display, but the staff is very good. Sometimes they're in slightly bad moods and seem like they don't really want to talk, but frankly I think that's to be expected at just about any buisness. I don't take it too seriously. Anyways, if you ask them a question, they always answer enthusiastically, and if they don't know the answer they'll ask one of the other staff members.

It really helps that most of them are also bike commuters and love riding bikes as a hobby. When I bought a new bike there about a month ago they fitted me, let me test ride a few bikes, told me what the general opinions of the bikes were on biking forums, and they ordered the model I decided on in my size. They took the time to explain lots of things about the bike and accesories I purchased. That sort of service is priceless.