Hi CV, I just built my system a couple months ago (I also got an Intel hook-up), so I still have a bit of knowledge floating around my skull.

If you don't care about overclocking, I can recommend Intel's own D975XBX2 (aka "Bad-Ax 2") motherboard for almost guaranteed compatibility. If you're serious about using your PC as a media center, you can get the version that comes with on-board 7.1 sound (complete with digital outputs). Plus it has gigabit ethernet and plenty of SATA ports. But it uses PCIe instead of AGP, so you might be limited in how cheap of a video card you can get.

A warning note about Vista is that the sound stack for Vista has been completely changed from XP. As a result, pretty much all sound cards are having major driver/compatibility issues. So if you were planning on using a card instead of using on-board sound, I highly recommend doing some serious research first.

As for RAM, I'm using a pair of 1G Crucial Ballistix (BL2KIT12864AA804) in dual channel mode (which actually seems to be perfectly adequate for Vista 32-bit). I stressed tested it all night with Memtest and had no errors, so I think it's reliable enough. But if you don't mind spending a little more, Kingston memory has just about a 100% compatibility rate with Intel mobos (Intel uses it in-house to validate their high-end systems).

I would also recommend staying away from DDR3. The compatibility problems with DDR2 memory is bad enough. I don't expect DDR3 to gain mainstream support until next year when the successor to the Core 2 Duo comes out. In the mean time, I don't expect DDR3 to make a big amount of difference since the Core 2 Duo (even 45nm) was not really designed to take advantage of that kind of bandwidth.

For video cards, if you're thinking about getting a Blu-ray or HD-DVD drive for your PC, I would recommend nVidia's GeForce 8600 ($150). It has full H.264 decode acceleration in hardware, and will enable to you to decode hi-def video streams with ease. If you're a gamer, you'd be a fool not to get the brand new GeForce 8800 GT. It's ludicrously overpowered for the price ($200-250). By contrast, I bought my 8800 GTS just 2 months ago for $300, and the 8800 GT just slaughters it in every benchmark (I'm almost kind of pissed at nVidia now).

If you care about the amount of noise your PC makes, I'd stay away from older video cards like the GeForce 7 series. The new 8 series are significantly quieter. Even my "high-performance" GeForfce 8800 GTS is virtually silent.

I'm got a Corsair HX520W power supply which has been rock solid and completely quiet so far. Combined with a P180 case, you can't even tell if my PC is on most of the time.

I also got a free Western Digital 160G drive that is silent, but it didn't come with a box so I'm not exactly sure what model it is. Seagate Barracudas are supposed to be extremely quiet as well.

Let's see, I think that covers everything. One other word of advice, I don't recommend waiting to "see what happens with display devices." Personally, I think HDMI is a crap format that is already becoming obsolete. I recommend either sticking with DVI and getting something good now (any HDMI signal can be converted to DVI) or being prepared to wait a long time. HDMI is not going anywhere, and the successor to HDMI is quite a ways off still.