I currently use my 770 (with HE2007).
It's my primary "couch" companion - browsing,mail (imap via claws mail) and vnc control to server/HTPC when needed.
I'm very tempted by the n810. If I get it I would broaden out the use to include it as travelling companion, meeting companion and media player. This is of course possible with the 770 allready - but it is too unstable to use for work.

The only thing holding me back is the "old fashioned" charging. I recently bought the Nokia 6500 classic phone, and love the micro usb port for everything.
Why the heck didn't they implement this with the n810 and keep the minijack (i just hate having 5 different chargers around the house).