New HTPC Case, CPU & Board

Hi i have a few quid to upgrade. I think about £500.

My main PC is a Q6600 with 4gig of Ram and a Asus P5k-E board. I am thinking about moving that in to a new case and using these components for my HTPC.
Question 1.
HTPC case that will hold a full size board? any recommendations?

As i will be moving the futs of my main pc in to the HTPC i will need new RAM, CPU, Board and water block!! for my main PC. this PC is used ONLY for gaming. i have a 4890 GPU and i am very happy with it.

My budget is the change from the case for the GTPC, i think about £400. I am open to the AMD / Intel debate and i just want the best bang for buck!

Using a SilverStone LC20S here, takes full size atx mobos and PSUs. It's also probably the cheapest full-sized option without using a standard PC case. It costs around £80 with no PSU.
That leaves you ~£300ish for the rest.

I see scan have this combo deal on today only for £280....seems a fairly good deal and would leave you around £40 for a waterblock (or a mounting kit for the one you have if that's an option).

Of course, there may also be the additional cost of a PSU for the HTPC....