Get some Dekoni Elite Leathers, a decent DAC/Amp, EQ the treble peaks at 8k and 10.5k down a couple db, boost the mids at 1-2k by 1db or so and you have the best closed back headphone under $200. Very clean bass and treble resolution for this price range. Also has excellent imaging and a wide soundtage for a closed back. Highly recommended for both gaming and music (Although I find equalisation mandatory for music otherwise this headphone is too sibilant).
downblueytFor headphones under $250 still the Beyerdynamic DT770 80 ohms with Dekoni Elite Leather pads are #1 for me, if only closed backs are considered. For open backs I would look into HD58X/HD560S/HD6XXs for music and for gaming - (Ordered from most "fun" sounding for immersion to most suitable open backs for competive FPS gaming) - Beyerdynamic DT990s - AKG K702s - Audio-Technica AD700Xs