I've been using an Aark 24/96 for a while now and I am delighted with the performance. There are reviews on the web, I recommend you have a look. I chose it because experience has taught me that a PC used for sound-recording should not be used for anything else. Sound cards are demanding beasts and resent having to share system resources. I have an old PC. 233 pentium1 MMX with 64Mb ram and a big hard drive. this is the minimum spec for the Aark24/96. The card that goes in the pc has a complete recording system on board that works almost independently of the PC so you don't need a flashy pc to run it. The package comes with cakewalk proaudio9 which I don't find easy to work with. I use CoolEdit pro. You can amplify a signal that is barely audible up to full strength and there is virtually zero added noise. I was not familiar with 24bit sound quality before i bought this kit. I was astonished by the clarity the Aark gives to accoustic sound.

It's an option worthy of consideration.

http://www.aardvark-pro.com/pc_audio.html