Hey guys, I've been reading a ton and I wanted to get you guys' opinions. I'm looking for a headset setup for 360 and PS3 gameplay and movie watching. My wife scorns me when I wake her up while blasting bad guys at night.

What is important to me:
-Positional sound. I want to head bullets whiz by and footsteps behind me. From what I am reading you don't necessarily need a true surround headset to get that?
-Comfort. I have a fat head.

My setup currently:
YAMAHA RX-V565 7.1-Channel Home Theater Receiver
XBOX 360 and the PS3 connected and switched through the Yamaha.
I already have the Audio Technica AD700 headphones so I was thinking I would buy the Astro mixamp and use it with those. I just need a mic solution for voice chat on 360 and PS3. Then, when I can afford it I will upgrade my headset to the Sennheiser PC360s or other higher-end headset. Also, is there a way to hook this up so I don't have to switch back and forth the cables for 360 to PS3?
Either that or I could buy something like the PX5 or Tritton AXPro sets or something like that. What think?
Any suggestions are very much appreciated. Thanks.