[PrinnyG]

I'm pretty new to the audiophile scene, and I'm looking for closed cans like Beyer's DT770 Pro, 80ohms; or AKG K550 to replace a usb headset of mine. Closed headphones is definitely a requirement.
 
I do a lot of gaming (mainly competitive fps like quake, tf2, css; with a few immersive mmos, and Dota 2), and I  also listen to a lot of music (huge variety-- from Rock, pop, kpop, metal, orchesta, techno, rap, etc), and I will be mainly using it at home. I also watch a lot of movies and anime-- so I do prefer decent bass.
So I think i need a headphones that's pretty balanced and have good soundstage for gaming. 
 
I also need to know what I need to power said headphones (like soundcard and amp/dac). 
 
My budget is probably around $350~ (though I may raise my budget to possible $450+ if needed), so maybe 250~ for headphones and 100~ for soundcard or whatever. I'm not sure if i need an external amp/dac along with the soundcard though, I'm pretty new to this sort of thing..
 
Any suggestions?

 

[Roller]

Considering you do competitive gaming, you should get a X-Fi powered soundcard, especially the flagship Creative X-Fi Titanium HD. X-Fi powered cards have full gaming audio support, including hardware EAX up to version 5, hardware OpenAL and positional cue improvement algorithms that aren't available on soundcards from other manufacturers.
 
One of the very best headphones for competitive gaming is the Audio Technica ATH-AD700, it simply excels at that. However, it is rather light on bass and won't provide a satisfying experience with immersive gaming.
 
Optionally, you can add a headphone amp like a JDS Labs O2, or a lower priced PA2V2.

 

[PrinnyG]

I'm thinking about going with an open headphones like DT 990 Pro, 250 ohms.
If I buy that alongside a Titanium HD, would I need an external amp to properly power it? If an external amp is really needed what's the best I can get for hopefully under, or around $100?

 

[Roller]

It is recommended to add a headphone amp to the DT 990 Pro 250 Ohm. Given your specified budget, the Fiio E9/09K is your best option.