Stick with newegg! A friend got burned royally at ZipZoomFly some time back while newegg and TigerDirect generally stand by what they sell. Newegg simply sees some of the best prices.
The alternatives to the three vendors named there would typically be shopping sites like amazon.com, nextag, and a few others. Amazon is particularly good for seeing older items found there while not seen on the usual vendors depending on what you are looking for.