As far as full qwerty phones go n Tmobile, you need to decide if your thinking smartphone, feature phone or blackberry(I like to separate these from smartphones).
From what it looks like, new blackberry phones (which also have really nice qwerty keyboards in my opinion) could be the Curve 2 (Javelin/8900) and a very much rumored Bold (I have nothing to confirm the existence of this phone on tmobile but I'm not the best person to ask either).
There is always the G1, but you have to like that style
Personally, I'd be waiting for the HTC wing II. From what I've heard its supposed to be like the HTC touch diamond pro or something similar to an HTC touch HD pro (so a touch HD with a slide out keyboard), which is a device I really like on Verizon and AT&T.
I guess there is the dash II too, but thats not nearly as flashy as any of the other mentioned phones.
You can also get an unlocked Nokia E71 or a Sony Xperia X1over at Best Buy (but I don't think you'll get 3g on either of these phones)