I personally have the Medusa 5.1's and enjoy them greatly for watching movies in 5.1. However, in game, attempting to use 5.1 results in poor positioning for some reason. I'm sure it depends on the game, but in every game I've tried (F.E.A.R., BF2, CoD and CoD2, HL2, CS:S, CS 1.6, and a few other random FPS) the positioning is more accurate with just 2 channels. They are comfortable and sturdy but heavy if you wear them a long time.
I think sound quality has a VERY important impact on being successful in FPS games. I'm on a current top 3 team for CoD2 in the USA and have previously played MOH:AA and CoD 1 on the best teams in the USA as well (feel free to look up the history for end-effect and [BoRo] in CEVO, CAL, TWL, GGL, and SG). My point in mentioning this is not to brag, but to show that I know what's important when prioritizing the factors that go into gaming successfully. Headphones with MINIMAL, tight bass (yes, you read that correctly) and clear mids and highs are a necessity when playing. You want the bass from a gunshot or explosion to be over and done with ASAP so that you can hear footsteps and the clear differentiation of your teamates on comms. Sure, booming bass from an easy-to-drive set of cans might be great for immersion in single player, but in competition where positioning of the enemy is of paramount importance you want less distractions and more clarity in the proximity of footsteps.
In short, for
competitive gaming you want:
2 channels
Clear mids and highs
Lowest possible bass
Great comfort (raw ears distracts from gameplay
)
Separation from outside noise (only important when LANing or in another loud environment)
Now that you know what a gamer needs out of his headphones, the guys here with more experience will hopefully point you in the direction of a pair of cans that fits the bill
. The HD280's look like they'd probably suffice from what I've been reading.