for lowest prices: eBay, but you've got to know what you're looking for.
Otherwise, www.bhphotovideo.com has an incredible selection, loads of specs & pro reviews on-line, and highly-experienced staff available on the phone. Almost everything is in stock. Strictly straight shooters (pun intended) who won't pull any flim-flam -- a lot of their business is pros. If they're prices aren't the absolute lowest, they're only 2-3% higher than fly-by-night box shops with zero inventory, and their knowledge & business practices are worth that many times over.Fletcher James
Levit & James, Inc.