I actually played a game or two with these and I have to say that really changed my tune drastically.
While my music may not be as punchy I guess as I wanted (the song in particular was http://ocremix.org/remix/OCR00969/ which is a 160kbps MP3 file, a few 256kbps files in my audio directory and one 320kbps.
But I say again. The quality difference when playing GAMES really just made the sounds quite detailed and crisp. So these headphones are great, but NOT for the reason I intended, hah.
Yeah mate the AD700 just won't have the bass/punch that you desire (for that particular song/genre). You might actually get used to it's bass-lightness, I kind of did when I had it.
Even with the AD700 fed from my Audio-gd dac19 and amped by a beta22, they just don't have any balls.
But it doesn't mean you can't enjoy it for other things!, I'm just trying to prevent you from barking up the wrong tree with the AD700's ^^.