Your requirements are pretty modest, actually.

I'd go with either the N810, because you get the keyboard for rapid text entry and the best browser, or the N770, because the coveron/off is extremely convenient and keeps it from getting damaged --- plus, it's all of $100.

Downside of the N770 is lack of OS support and an older browser. The N800 is a viable option too, but the N810 is, for you, superior in every way --- smaller, lighter, and has the keyboard.