Ah right, that gives me a bit more to work with! So by no bigger than an AV unit, I presume about the same size as an AV amp should be ok?
Right now I'd actually recommend an SSD for the OS and an external drive (seems silly but if you look around, they're actually cheaper than buying the drives 'neat' in many cases!!) for his media. The SSD will be silent, ensure the system boots quickly and give him a fluid windows experience. The external drive will be easier to move around and replace, and also can be exported between machines more easily.
To be fair most games don't rely on HDD speed massively, so he wouldn't struggle in most cases aside from longer loading times with USB 2.0 but a USB 3.0 drive would be better.
Shadow boxer has given a good spec there, so what I would post would actually be quite similar, however the caveat being he hasn't included much storage which is kinda important for a media PC.
Also, as a HTPC, I'd focus more heavily on the noise produced by the various coolers
There's also the option of the GPU. I've personally opted again for an Nvidia card, as I found their hardware accelleration a LITTLE more robust over a very wide range of files. The 550ti isn't that far from the 460GTX, but consumes a little less power, and produces a little less heat. Which means it is likely (bad fan choice aside) to run at quieter, idle fan speeds more of the time, and will still game comfortably at reasonable settings.
I would ALSO suggest considering going for a G6/8** Pentium series right now (they're STILL sandybridge, and are FASTER than the first gen I3s), and then upgrading if he finds he requires a quad core, or with Ivybridge. The I3 are good processors, and are faster than the Pentium's, however for media playback either will be more than enough in 99% of cases, and whilst the I3-2**** will be faster it's unclear if he'll need it. The money he would then save could be spent on more storage, or kept aside for that future upgrade when Ivybridge quads appears in about 3-6 months. The Pentium Sandy's are actually only slightly slower than an I3-2**** processor when it comes to gaming, and that's more down to the higher clock speeds than anything else. I opted for an I3 inside my media pc as I got it at below usual price, otherwise I probably would have got an G840.
Anyway, money and some slight spec differences aside, here's my spec:
OcUK GeForce GTX 550Ti 1024MB GDDR5 PCI-Express Graphics Card £94.99
Crucial RealSSD M4 64GB 2.5" SATA 6Gb/s Solid State Hard Drive (CT064M4SSD2) £82.99
OcUK Value 1TB Memory Tower Black 3.5" External HDD (USB2.0) £79.99
Microsoft Windows 7 Home Premium SP1 64-Bit - OEM £79.99
MSI H67MA-E35 Intel H67 (Socket 1155) DDR3 Micro-ATX Motherboard - (Sandybridge) **B3 REVISION** £61.99
Samsung SH-B123L/RSBP 12x BluRay ROM / DVDRW DL & RAM Lightscribe SATA-II Optical Drive - Black (Retail) £59.99
BeQuiet Pure Power L7 530W '80 Plus' Power Supply £39.98
OcUK Opera Media Case - Black £39.98
Scythe Shuriken Rev.B Quiet Low Profile CPU Cooler (Socket 939/940/AM2/AM2+/AM3/LGA775/LGA1155/LGA1156/LGA1366) £27.98
Kingston HyperX Genesis Grey 4GB (2x2GB) DDR3 PC3-12800C9 1600MHz Dual Channel Kit (KHX1600C9D3X2K2/4GX) £19.98
2* Xigmatek 120mm Crystal Red LED Fan £13.96
Total = £655 inc VAT + Postage
Now I’ve specced a Sandybridge Pentium as mentioned as earlier, they won't be as fast as the I3, but they're still good dual-core processors (like I stated before, they're faster than the first generation i3 processors in many cases!) that will still cope even with games, will run cooler and absorb less juice than an i3-2*** processor, and the extra cash goes into the storage drive, as we’ve already peaked budget slightly.
I have one of those coolers in my HTPC and if you lower it to run 75% speed in BIOS or even 50%, it's bloody quiet, I'm using it with an i3-2100 so eithe the I3 or the Pentium G6/8 chips will be more than fine with it. And I was picky when it came to building this system and noise (half the system is passive).
If your brother isn’t planning to play BD’s, I’d drop the Blu-ray instantly as it’ll put it under your price range, and he can then add an optical drive at a later date.
