[ul]
vim
bc
screen
rsync
sar
[/ul]

I wanted to mention FUSHI fushi.sf.net which is a pretty good way to learn command line, mostly the commands you guys have covered are in FUSHI.

Same as above but I'd add:

[ul]
[li]htop[/li]
[li]mc[/li]
[li]ethstatus[/li]
[li]pbzip2[/li]
[li]debootstrap[/li]
[li]ccze[/li]
[li]ethstatus[/li]
[li]listadmin[/li]
[li]fakeroot[/li]
[li]strace[/li]
[li]bzr[/li]
[li]dput[/li]
[li]irssi[/li]
[li]toilet[/li]
[li]figlet[/li]
[li]sshfs[/li]
[/ul]

Hmm, maybe too many to list :)

ls, tar, vim, grep, less, sed, cat, chmod, echo, iwconfig, dhcpcd