I am a huge David's Tea fan, but Teavana is a close second.
With either store, all of the teas are kept behind the counter and you need to ask for help - I can understand for health reasons why they would do that. When buying loose leaf tea, do you really want any Joe Blow off the street sticking their hands in the cannisters???
I do find Teavana to be more expensive than David's - including for their teas to go. But it is a close second and they have several mall locations for healthy drink alternatives at The Core, Chinook, Cross Iron Mills.