AMD systems don't use FSB so that isn't an issue. They use HyperTransport. Also, you don't need RAID in an HTPC. Quad cores can work well, assuming, of course your applications can use all four cores, which many cannot. A quad core will be overkill here, in my opinion. The problems related to using ATI or NVidia may come from how drivers handle the media input. I assume you're in the U.K. since you mentioned the BBC. You can use any graphics card with any motherboard. The exception to this lies with using Crossfire or SLI, but a HTPC shouldn't be using those anyway. If you want to use on-board NVidia graphics, the MSI NF750-G55 nForce 750a SLI Socket AM3
will work. Use that with DDR3 memory like the OCZ 4GB Kit (2x2GB) DDR3 1333MHz/PC3-10666 Gold Dual Channel CL
and you will be set. Also, the GHz. in multicore processors do not stack, so if you have a quad core CPU with 2GHz. in each core, you don't have 8GHz. Instructions are processed only as fast as the core processing them. Also, not all programs can use all four cores, limiting them to one or two. In this type of situation, clock speed will play an important factor in performance since one or more cores aren't in use.