DazZ. said:
But I highly, highly advise Torchlight. It's pretty much Diablo, and it has a netbook mode in the options. A very good ARPG with tons of good mods already out.
Was going to mention this myself. I play it on my laptop (not in netbook mode, as it's sufficiently powerful) and it's quite a good game so far.
It's not a hugely complex game imo, so it's perfect for playing now and again, as there isn't a huge "what was I doing?" with it. Even if you do forget, you have a quest log

.
There's also puzzle-y type games. Not sure if I tried Eets on my notebook, but imagine it'd work fine. If it will play nice (I think I had it working under XP) and you can find a copy, The Incredible Machine is a game very much in the same vein (and used to be a firm fave when I was younger).
With my laptop (and previously my notebook when I had it) I have a Logitech V470 bluetooth mouse. If you have a bag that can store the charging cable (I found a nice Tech Air bag for my NC10) then it's worth getting one imo. Seems to work well on most surfaces, including my leg and the edge of my laptop lol.