Now then. First, congratulations to Ducky: another person learns that HTML isn't a programming language.
Seriously, being able to program (and, preferably program
well) in C/C++ is a great skill to have. There are a lot of other good languages to have, namely (in my opinion): Perl, Python, LISP (not so much anymore), and Java (not Javascript, which is just good for making webpages do stupid pet tricks). Assembly isn't so useful anymore, since C/C++ offers you all the control assembly does along with being a high-level language... but if you're going to be writing an OS anytime soon, or if you have an intense desire to screw around with your computer, you damn well better know it.
Languages which (also in my opinion) suck, listed in alphabetical order, are: BASIC/VB. That is all.
BASIC is not even good for writing DOS programs/games, since they will end up with horrible, crappy graphics and sound, will be slow, and cannot reach the complexity of programs written in C without becoming unmanageable. And then, of course, there's the fact that you can't create stand-alone EXEs. VB is completely unportable (well... so is BASIC O_o), it doesn't offer much hardware control, and teaches bad programming habits (again, so does BASIC, which makes me wonder why they teach BASIC in school computer courses...). GraalScript also sucks because it teaches bad programming habits.
At the same time, though, it's so
fun to screw around in.