Programming! It's the death of me! Seriously, programming rocks. There's nothing I can't do when I'm at the shell prompt about to make a program, hehe...

Anyways, onward with the list:

C: good language for low-level programming. Can write/read data from files/descriptors/memory/etc... Sucks ass on string interpolation. You have to compile the code so something like
GCC is needed.
C++: not much on this I know about, a "better" C.
Perl: the almighty-do-everything interpreter (on the fly, no compiled exec needed). Does everything from text file manipulation (what it's made for) to database reads/writes to cgi to page formation, etc...really good stuff.
Shell: various shell programming (bash,sh,tcsh,zsh, and others) allows for high-level programming that sometimes is the best solution for quick-n-dirty programs.
VB: visual basic...spend one day with this and you'll be able to do anything that Windows can throw up. Pretty easy to learn but VB "writers" I don't consider real programmers, hehe...
Java: great server-side programming that Sun created. Can create standalone apps or web-interfaced programs. Good stuff. Currently on 1.4.1 beta right now at http://java.sun.com .
HTML/Javascript: very good to know as webpages revolve around HTML. Nowadays, you don't need half the tags that you needed a few years ago so it's even easier. Do it with notepad/vi/emacs/etc, and not with Frontpage. You can't even remotely call it "programming" as it's not a real language and it's even less if you 'drag-n-drop' from Frontpage or any other GUI driven program. Maybe I'm biased, but the keyboard's there for a reason... Other things that involve the web is flash/shockwave.

Hope this gives you an idea of what you can do with programming and helps you on your way.