M-Audio, Yorkville, Mackie, Edirol, Yamaha... The list could go on forever. Or, at least a few more lines of text.
Go to your nearest dealer with a few CD's and pick the ones you like best in your price range.
Don't cheap-out, though... Your monitors are your first line of defense. All the gear in the world doesn't mean (EXPLETIVE) if you can't hear it accurately.