Depending on where you live, there are probably decent tea shops (or, failing that, gourmet or health food stores with decent tea selections). It's nice to be able to smell different varieties, try samplers, etc.
That said, I've had consistently good experiences with Adagio, and (once you know what you like) tea is well-suited to mail order.
That said, I've had consistently good experiences with Adagio, and (once you know what you like) tea is well-suited to mail order.