I have an old USB Logitech G35 that I have had for many years. My wife and kids bought me a Sennheiser HD 598 Headphones as a gift. I normally use headphones for mostly gaming, with streaming video, mp3's while working etc.. etc. I was looking for options for a soundcard that would best work for this. I haven't owned a soundcard since Windows 95-98.
I've done some research tonight and I seem to find either Creative or Asus Xonar products as the most recommended. The one thing seems to be mentioned the most is headphone amp's. As far as a budget under $200 is preferred but up to $300 is fine.
Running Windows 7 64bit, Nvidia GTX 670, Intel chip, 16 gigs of RAM. Incase you need that information. I have a PCI and PCIe spot open.
http://www.newegg.com/Product/Product.aspx?Item=N82E168... That is what I would go with. I don't recommend a pci card as you will probably want to keep your card for your next build and most boards won't have pci then as many don't now. I would stay away from Creative cards too, they have had a host of issues in the past.