6700 = cheap thrills (with rebate and $150 off w/contract, $250-$300)
6800 = full price ($550? so $400 w/2 year contract?)
If it were me (and it was - I got my 6700 end of October) I'd get the cheaper one, skip the 6800, and get the one after it
Dunno what the 700wx runs cost wise, but I think its also not going to cost as much as the 6800 and is also a good choice - I prefer a larger screen/keyboard & wifi of the 6700.
This forum will take better care of you then sprint will, btw.