Dave and Adams are pretty much all I use these days, though it'd be nice if Steel City or Blowout made it easier to buy for us OS people. Sometimes they have stuff D&A don't, or have a special I'd like to snag
As tak35bne says, right now the dollar is pretty bad - you need to add near 20% to any order. D&A shipping is very good, but can be expensive for small orders as I think their shipping starts at around US40 for the 3 day service. But as has been said, if you buy a bunch of boxes you can spread that shipping cost and make it easier to swallow...
I've got an eye out on D&A for Black Friday bargains....and will likely have some boxes to break over Christmas if all goes well...