questions about buying accessories

This is to all fans, but particularly those in the Toronto area (if there are any yet!)

1 - Where do you buy your accessories? I see Henry's might be a good place to go, but they have high prices -- is it safe to assume that they can be haggled to more reasonable prices, much like when buying music gear?

2 - What are your opinions on: battery grip, remote shutter control, spare battery, macro lens, prime lens, filters, etc... I'm new to this so the more information you want to volunteer the better!

Thanks...