ntfs-3g to write to ntsf drives
cups for printing
sane for scanners, then xsane and simplescan
the print.pdf driver
kmymoney for personal accounting
gnome disk utilities (along with gparted that has been mentioned already)
grsync (graphical rsync utility)
cheese photocapture for your usb camera
and a bunch of others, but already mentioned.
Kind of amazing what you can do with these suckers.