Emulators - Amiga, PSX, N64 (if possible), GBC, GBA, DS?, NeoGeo, MAME, C64, Atari/AtariST, Spectrum etc.
Media player - unconverted videos (DivX, Xvid, h/x264 ...)
Text/document reader - mainly PDF (RetroGamer for example ;) )
Inet communication - web/ICQ/IRC/email at home/hotspots via WIFI...