Monitors, every time.
My Adam A7s >>>>>>> NAD C352 driving B&W DM602s >>> NAD & KEF C40s >>>>>>>>>>>>>>>>>>>creative amp&sub & JBL Control 1Gs.
Cheaper too (than 2 out of the other 3).
Its more than just EQ levelness, as well. Its how dynamic and fast the speaker is, its ability to resolve layered and otherwise concurrent sounds, differentiate attacks in notes that are close together, ability to only represent whats there, rather than always make everything sound good (whatever that manufacturers version of "Good" is), and you evade the nightmare and cash cow of amp/speaker pairing. Pay not very much (200 or so or more) and you get bi-amplified speakers with matched amps.
They all still sound pretty different, and you still have to learn them, but youre off to a much better start with monitors than Hi Fi speakers. I mean, monitors and Hi Fi speakers look very much alike, but they're for very, very different jobs. If you get good enough monitors, you'll wonder why half your music suddenly sounds so rubbish, and you wont be able to listen to MP3s any lower than 320kbs, for a start :D (upsampling media players are your friend - foobar or a plugin for winamp)