If you go the AppleTV route, this is quite cool. I've used it in the past and I'm going to try the new version. Allows you to use your AppleTV to stream Pandora (YAY) and a bunch of other content, including Hulu. The support forums are very good. It's based on XMBC.
A quick google also shows that Boxee supports FLAC too.
Install is quite easy, I set it up on my Mac. The hardest part is finding a USB stick that's bootable.
http://blog.boxee.tv/2010/02/25/get-a-bite-of-this-%E2%80%93-boxee-beta-on-appletv/They have versions that work on Mac/PC/Linux so you can try out the GUI beforehand.
