IRC (probably ssh to the box running irssi+screen).
All the usual mail/web/calender stuff.
Some EBook reading, some games, some im and voip calling.

And hopefully, if the battery is good enough (or if I can find one which is) as GPS for walking and cycling trips.

And, if I find the time to do so, some experimenting with mobile IPv6, but changes are I won't find that time