Just recv'd an order from liveaquaria, online.
I don't know what other people's experiences have been with them, but I'll have to give them a thumbs up after this first time. They ship plants on Mondays, so I got my order on Wednesday around noon. The facility is somewhere near Chicago so they didn't have to travel that far, at least.
Shipping wasn't cheap (~$15) but the plant prices weren't that bad, so altogether, with a larger order it worked out pretty well. Everything came in looking crazy excellent and healthy, plus I ended up getting more plants than I expected.
That being said, I'd prefer to buy from LFS in the St. Louis area, but when pickings are slim, online options aren't all that bad.