So I have been looking to pick up a good pair of headphones (I have heard good things about Beyerdynamic's DT880 and MMX300) and I am wondering what the exact point of using a sound card is. As if I pick up DT880, depending on model I will most likely be getting an amp (Which if anyone knows a good one, could you recommend please!), and I see a far bit of talk about sound cards (X-Fi?). What exactly is the point of them and will it be worth my while getting one? If show, could you recommend a few please!