I buy stuff at the local Canada Computers in Toronto. A few of the guys there are actually very knowledgeable, which is a big surprise for the stores around there. The prices are are good, but sometimes
Sonnam's are better.
Both the above named stores have 15-20% restocking fees and I think won't return cash, just credit. I just bought Firewire card from Canada Computers and it doesn't work with my PC. But they told me right up front about the restocking fee, so I have no probs paying the 7 bux. (Defective parts are free RMAs, but I can't be bothered to run home and try a replacement of the same model, over $7.) Luckily they sell several other brands of Firewire cards and they actually have lots in stock, so I can swap for them instead. I'll tell you how that goes. However, I've only ever purchased in store. Dunno about online.
My dept. got roughly $4000 worth of equipment from sonnam. They were polite despite the fact that it took us a month to actually pay them. (Government institutional purchasing dept.) However again, I've never purchased from them online.
www.pccanada.com is another store. They seem fairly efficient online, but the only time I ordered online from them I got a Linksys router. It came, seemed to work as a switch, but refused to run as a router. They took the RMA no questions asked, but I actually physically drove to the store for the RMA, since they're in town.