I've been looking at the Emotiva stuff since Sonnie called my attention to it. It is impressive for the money.
http://www.emotiva.com/products.html http://emotivalounge.proboards54.com/index.cgi
One possible approach that might fit your criteria would be a new Emotiva amp and some sort of used pre-amp since you indicate not needing the latest decoding (due to your computer), and also want to upgrade the pre-amp later on. I would think with the new audio formats and HDMI 1.3, there might be a number of used pre-amps come on the market.