Choosing an External/Internal Sound Card

Hey all, I am going to purchase an ASUS Z96J notebook (I know, I know,
it's not IBM) from www.agearnotebooks.com, and the thing is that it has
very bad sound, as all laptops do. I was wondering if I would be able
to find an external sound card which works well, or an internal sound
card which can replace the one which came with the computer. So...:

1) Are there any worth-while external sound cards (USB 2.0) available?
2) Are there any sound cards which I can purchase to replace the one
which came prebuilt?


Thanks in advance!