Need advice on an audio interface for windows 7

[Harry62]

I made a thread a while back but it didn't help much. Here's my situation:

I need an audio interface just for monitoring what my computer(DAW) is playing. I have yet to find one that doesn't have 1 or more inputs for microphones and such. Anyways here's my specs:

-Windows 7 (can't remember but almost positive it's 32 bit)
-USB or Firewire (if firewire then I'll need a firewire card)

My current monitor setup is 2.1 (left, right, sub). I found these two interfaces and was wondering if either will work for what I want and if they will work correctly with windows 7(I keep reading horror stories on using interfaces with windows 7). Price range <=$500

#1
Amazon.com: Focusrite Saffire 6 USB Audio Interface: Musical Instruments

#2
Amazon.com: Focusrite Saffire Pro 24 Firewire Audio Interface, (SAFFIRE PRO 24): Musical Instruments