It definitely depends on what i'm buying... If I'm buying cigar related accessories or humidification devices, 99% of my business goes to heartfeltindustries.com They offer amazing products, at great prices, and the customer service which I've dealt with several time, is second to none.
If I'm buying cigars online, well my sources can't be revealed here :bn
I've bought a lot from CI and Famous though. Tampasweethearts has a great selection of stuff that I've been wanting to pick up, but I haven't gotten around to it do to other purchases.