This is my idea of base gui applications that can get any user started comfortably without burdening him or the system down,
Internet:
wicd, iceweasel, clawsmail, transmission
Audio-Video:
smplayer, gmusicbrowser, radio tray
Graphics-Image:
nitrogen, mirage, xfce4-screenshooter
Programming-Document:
mousepad, geany, evince, abiword, gnumeric
File-System:
spacefm, gnome-disk-utility, gparted
Utilities:
arandr, roxterm, clipit, bleachbit, lxtask, conky, volume icon, tint2, P7zip, xfburn, synaptic package manager
Cheers.