It depends on what you'll do with it.
The Elite X-fi is more for Audio Hobbists. Extrenal Contoller, remote, 64MB XRAM & comes with a few audio creation programs.
The Fatal1ty FPS I have. same card as the ones below but has 64MB XRAM and a front panel controller & remote.
The platinum is the same as the FPS without XRAM
The Extreme Music is good for gaming, music and entertainment 'movies". No front panel or Remote or XRAM.
If you don't have a very good set of speakers, 5.1 to 7.1, don't bother with the x-fi... go with the other recommended Audigy 2 ZS.