I've been rockin' a pair of Turtle Beach X4's myself for a good year or two, and have been thoroughly pleased with the overall quality of these headphones.
Anyhow, I also own a pair of X1's, but the amount of cords needed to hook everything-up is INSANE. Not to mention, they also require a USB connection to work. Otherwise, the audio quality is pretty fantastic.
In regards to the X4's, I purchased them for about $200 bucks - although, they can be found for "much cheaper" nowadays if you know where to look.
Trust me, "Wireless 5.1 Surround Sound (or 7.1 with the X41's)" is UNQUESTIONABLY the way to go, no doubt about it. Then again if you only plan on spending $100 dollars or so, you should probably stick with either the X3's, or X31's (both are Stereo only).
Whatever the case may be, my X4's run-off an IR Transmitter, so you need to be in a direct "line-of-sight" with the Transmitter itself for them to operate properly, or else the sound will cut-out.
Some folks also claim they'll hear a small "hissing noise" when it's completely quiet, but I've never had this problem myself. Lastly, the battery life (2 Triple AAA's) should last a good 20-25 hours before they need to be replaced.
The X31's and X41's (the newest line of Turtle Beach) both run off an RF Frequency, so you can walk around (without a direct-line-of-sight) and still hear everything.
The only potential downfall to "RF" technology, is that some Wireless Adapters might possibly interfere with sound quality - although, it shouldn't be a problem.
Best of luck with your next purchase.