What size screen would be best, and if a small screen, does DH have small fingers too, as some of the keyboards are far from ideal...
Personally I plug in USB keyboard and mouse when using any laptops, but then again, I power them from the mains (it would add to battery drain to use optical mouse and external keyboard on USB), but for me it means I can have an illuminated kbd for night use, with full size keys, no messing about like some laptops with three functions per key and no number pad.
Also that with a multimedia keyboard, it gives me sound mute, vol+, vol-, skip to next track, and so on. Sorry but I really, really, really, hate keyboards on most laptops, and whenever a client suggests buying a laptop I say to go into stores like Currys, Comet and PC World to try, and then look for any deals online when they know they will be OK with that keyboard.
Netbooks are smaller still, so even less chance of a number pad, lots of compromises about where the arrows go, and 2/3 uses per key, so even more reason to choose carefully.
If budget is tight I would completely ignore netbooks and get a s/h Windows XP mini tower on Ebay (at under 100 quid) and a decent size screen for 100-150 for a brand new 19" to 21" widescreen so movies and all could be used.
Sorry if a netbook is essential, but I feel some older bigger kit is better value (and add a wireless dongle for 5-10 quid off Ebay if you don't like cables to the router).