Given the larger budget available to you, you could dive straight into higher end stuff...
I would see if you could get a listen to someone's audiophile headphone setup with a DAC and some higher end cans, and see if thats something you would be willing in investing in.
As far as your microphone setup, that is completely overkill for gaming. Thats like home-studio recording, and even then you have better (cheaper, cleaner) options available to you, for example:
Pair that microphone with a desk stand (the stand it comes with is kind of crappy, a pop filter and a shock mount and you have equal quality without taking up unnecessary desk space for just a gaming setup.
Personally, I would go with a higher end pair of cans, and a DAC/AMP with an optical input and RCA or XLR outputs in addition to the regular headphone outputs or a DAC and a dedicated headphone amp. From there I would skip the sound card, and nab the Audio Technica mic with a good shock mount and desk stand for it, and grab a pair of decent studio monitor speakers. A decent option for a DAC+AMP combo would be:
with the headphone amp of your choice, this would also allow you to use non-USB microphones since it allows for inputs from mics. I lie, no XLR outputs.Edited by Xaero252 - 4/5/11 at 2:30pm