Should I get a sound card?

I'm getting into audio setup's and what not, and to start it off I want to get a good pair of headphones, so I decided on ATH-M50's. Heard they're good for both gaming and music. So I'd like to know from the community, is it worth having a soundcard? If so, which would be a good suggestion?

Forgot to mention, I'm pretty sure the headphones aren't 7.1, so I'm not sure which software's best for it. Anyone know which is better? The only one's I know about is Razer Surround, and Surround Blaster, and I think Dolby has their own.

I know there's a video on Tek Syndicate, debunking myths about soundcards, forgot the name of it.  something about "audio myths"    But, I bought an Asus Xonar STX soundcard, and I'm pretty happy with it.