well i dunno how succesful this site is. I am working on putting up a bit of my portfolio there now (and they have a very nice upload system by the way.... VERY effortless)
I haven't had any sales there yet, but I will hold out a little longer before judging them. Nonetheless they do have a nice site. I just noticed their 100% zoom feature. It works very well and gives the buyer a great idea of how the image will look.
Click on an image, then when you are on the individual images page, click the image again and a 100% view will come up.