Nope - much as I like new gadgets, I've been around the block too many times with too many carriers - and I'm way too happy with TMo to consider switching at this point.
When I get my hands on an N95, if I like it enough, I'll look for an unlocked one to use on TMo. Otherwise, I'll just wait a year to see what the next gen of phones looks like then - and if any of them appeal more than my Curve (but it would have to be *awfully* sweet to make me replace my Curve!).
Switch from TMo for a phone? No way.