Don't waste your time with the AD700's.
I bought them and they sounded alright. Then I went to a friends house and tried my current Razer Carcharias and holy crap the Razer's blew the AD700's out of the water. (Same Creative x-Fi Titanium cards at the time, now I have an Asus D2X). I usually listen to mostly metal and nu-metal, and the Razer's are excellent performers, while the AD700's were just ok. They were confortable though, but so is the Carcharias.
A lot of people here will just recomment the AD700's blindly because they got warped into buying them, and since the AD700's were the first thing they ever listened to, or comparing them to a dead system, think its a gift from God. Well they aren't.
I'm not an audiophile, but I know that metal should NOT sound like a pyro from TF2 talking, it has rhythm, not mppphmpphmmhphphphmmphmphmh.
Get the Roccat Kave, I've played with a review unit that really sounded quite nice. Definately better than the AD700's. Plus I was using preset settings on it's little control board, I'm sure if I tweaked it to my liking it would beat out even my current Carcharias
Get the Kave!