My mixes have been coming out muddy and bass heavy and it's due to the speakers I'm mixing on -- M Audio BX5. While the mix sounds great on the BX5 speakers, it comes out bad on normal systems (car, mp3 player, home). I have tried messing with the switches on the back of them and I know that I will eventually learn to adjust my hearing to mix properly on these, but until then I'd like to get a pair of good headphones that don't 'flavor' any tones: i.e. have a flat, natural response. What I plan to do is switch back and forth between the speakers and the headphones while monitoring. So, what headphones are the best for this that are under the $250 range?