We've shown you how to equalise just about any music program out there. Lifehacker reader beepbeeeepbeepbeepbeep gives us another good tip: if you must equalise, you should turn the frequencies you don't like down, rather than turning the good ones up.
A lot of people say you shouldn't equalise at all -- an argument we'll let you guys discuss in the comments -- but if you do, you should try to avoid raising levels:
stick to removing frequencies. Your computer is better at this than adding stuff. Better option: Get an old Sony amp or whatever, connect your computer, turn up bass. Sounds way better.
If you raise levels with a software equaliser, you're probably going to encounter some distortion, which will make your music sound worse, not better. Instead, find the curve you like, then "shift" everything down so your highest points are at zero. You'll probably have to turn your computer's volume up a bit to make up for it, but your music will sound much better.