Jas-e-tea ... the owner was an active member here, and turned his interest in tea into an online business. Can't say if he's still active here as a poster, but ... great guy when I dealt with him from time to time.
Yunnan sourcing. Another "guy who runs a business" thing rather than a big corporation, and one I like because the owner (Scott) really likes getting "clean" tea (ie, not coated in pesticides and such). Mainly he sells, pu-er cakes both from all the various tea houses as well as his own brand, but he sells lots of other types of teas too.
They have very good jasmine pearls, too, but they are incredibly overpriced. Get those from someone else, as excellent ones aren't all that hard to find.
They have a large selection, and the service is very good.
One of of favourites there is "Patisserie", a flavoured black tea that creates images of a bistro, with croissants etc.