N770, just picked one up off of Woot a few days ago for $100 flat. Upgraded it with OS2007HE and haven't had any wireless connection problems.
I'd say that if you need a budget touchscreen, the nokia may be the way to go. I saw an article recently where they wiped out all of the basic system software and put vanilla KDE on it, which would be interesting...I wonder if that would help speed it up?
Anyways, the N800 is reportedly faster that the 770, due to increased memory and can be had fairly cheaply as well.