if you're willing to spend, try RGO office furniture. They have a tonne of selection and high quality stuff. Sometimes they have some "as is" items in the warehouse as well.
I also picked some good stuff up at the the Govt of AB surplus auctions. They auctioned off a bunch of ATB furniture that worked out well for me. This was a special auction. The monthly stuff can be more miss than hit. occasionally some good deals on older tech stuff like printers, switches, modems, etc
http://surplus.gov.ab.ca/