[Bandzai]

Hi,
 
I've just bought a new PC with only integrated sound (Gigabyte Z77X-UD3H). I've decided that instead of soundcard I'd rather get an audio interface. I have problems choosing one. These are the requirements:
 
Budget up to or around $500.
USB connection (I was careless enough to buy motherboard without Firewire).
Mic preamp (I've got Shure SM58. I'm thinking of using it for gaming with headphones too. Need to get a comfy mount for it).
Input for electric guitar (all the guitar effect features would be as advantage).
And most importantly I would also like to use it for gaming sound output for surround sound on headphones (after reading this forum thinking of getting Ultrasone Pro 900). 
 
Or instead of audio interface would a mixer suffice? Something like Behringer XENYX502? Sorry if this is really stupid, I'm real noob still.
 
Thanks for your thoughts in advance!

 

[KiruDub]

If I understand what you're looking to do correctly, the main hurdle you're going to see is that no pro audio interface is going to give you 3D positional surround on headphones*, since that relies on decoder chipsets that are not called for in the pro audio interface world.
 
In my opinion, given that you can get a good entry-level USB 2 interface for $200...
 
http://www.sweetwater.com/store/detail/Scarlett2i2/
 
I'd spend the leftover $$ on a soundcard that will give you what you want for gaming, like a Titanium HD.
 
I've found it's better to use gear that's built for a specific range of needs, as opposed to looking at something that tries to span them all.
 
*I'm unfamiliar with the Ultrasones you're looking at, and I'm not sure how well the S-Logic works with PC games

 

[Bandzai]

Thank you KiruDub for your answer. I was afraid I was afraid it would be so, as I could not find one box, which would do everything I need.