Hi Julienne,
I'm in the same boat.
Love "stereo sound" but in the fold of revamping my old system.
I just picked up a pair of B&W685's and about to go from my Mac mini to amp via the "USB Thingee".
No joke, it's really called the " Thingee " by Blue Circle Audio.
Looks like the step sister of Frankenstein but sounds like an angle!
Best of all it's a 24-bit DAC for only $169.00 USD!!!
Here's a few links / reviews:
http://www.goodsound.com/equipment/blue_circle_usb_thingee.htm
http://www.bluecircle.com/index.php?page_id=7196
Anthony.