I've ordered from a lot over the past couple of years. I probably should give Kebco a shot, but there's a store in Canada with a one of every figure schtick as well, so avoiding customs holds some appeal for me.
Being a Canadian I rank them on different things. Nothing irks me more than padding shipping and I've had it happen a few times from this list. That said, shipping to the US according to their websites is at times free, and always cheaper than up north, eh?
I've had success with yestertoys, EE and newforcecomics.com. The latter is my current retailer of choice as I've been primarily ordering cases and singles/openers of items. Probably the most appealing thing is Rick's communication and totally fair (read you pay what it costs him/them) shipping. That's a huge plus for me. One of the other retailers I ordered a Vaders Tie from charged me shipping PLUS $12 handling
That was the last time I ordered there. Still a good company if you're in the US and great selection.
Legendsactionfigures.com in Canada is a pretty good site too. Not sure about the prices and how they work out for Americans though.