For a small and quiet front end with complete control over the DVR aspects of the server, I think you're back to looking at Myth if you want to roll your own all the way, or SageTV if you want most or all of it already done for you.

You might want to look specifically at SageMC add-on for SageTV which will change up the UI, especially making the movie library feature much more pleasant. I haven't installed this yet myself. Their new HD Theater extender box works very well, including its ability to scale your content to your display's native resolution.

If you're on a budget do look at receivers. If you can afford it, go separates because whatever power amplifier(s) you get along with speakers, can last years longer than the ever-changing requirements of an audio processor. It'll cost more but you might be able to fit it with your stated budget.

With regards to "unlimited budget" it's not even worth discussing except for "fun" because the prices can easily surpass a million dollars without trying very hard.

Right now I'm leaning toward getting an ATI power amplifier (not related to the ATI graphics company) with an as-yet undetermined preamp-processor (trying to keep that to about $1000). I'd like to get a DVDO Edge video processor (which will handle any/all video switching) and connect that up to a 52" Sharp Aquos (hopefully something new they release after CES).

For speakers, I'd personally like to keep it Canadian with PSB, but you might look for something locally in the UK, especially with such great products produced there. I don't know how much you'll save shopping a national brand, if anything at all however.

With a greater budget, but not going into the absolutely insane, I'd probably also keep the amplification Canadian and go with multiple Bryston amplifiers. Either a 4BSST for the front left and right (and music) along with one of their multi-channels for everything else. Or at some additional cash, a pair of 7BSST monoblocks for the front left and right. At that point I'd still be undecided on the pre-pro, though Bryston also make one of those. I'd still stick with PSB speakers but move on up their model line.