Thread moved to proposed setup forum.
personally i think that the MB/processor combo is way overkill for a car. If your really set on having that much power to play music and run a GPS go for it, but its going to consume a lot more power than you need to. I run a core2duo 2.2 and its plenty fast, and people even run 1.2 celerons and have no problems with videos, web, gps, music, and everything and their systems use very small amounts of power. Unless you plan on doing 3-d gaming i'd look for something a little less extreme. (we understand - we are all computer geeks too and our instinct is to always build the biggest baddest computer we can...)
if you do want to run a system like that I would recommend an Opus. They are a little more money but very high end and good with larger amounts of power.
For the HD, I would recommend going with a laptop sata drive, and if you want the speed of a 7200rpm drive (or faster) and great vibration resistance go with a SSD drive. You can get some cheap if you look. Search the forums here many people have discussed different brands and stuff.
Best of luck luck to you, hope to not have been too much of a downer, but I learned all these things the hard way and just trying to save you time and money.
But at the same time I hate power hogs. Are you running the Core 2 Duo E4500 2.20GHz Processor? If so from the prices I seen its almost 3x the price i can get the AMD cpu I posted. Why does it cost more? Brand name? Efficiency?
Also maybe I read wrong but, I though Intel processors have problem with heat in carpc situations?
I think a brand name board would be better...especially with PCI/PCI-e slots
You don't need 2GB RAM
CPU is fine I think
Why not get a SATA 3GB/Sec desktop drive? Cheap enough too...
Creative cards suck...get a PCI-e Xonar D2
X2 on the OPUS PSU....very good PSU's.
If power consumption is an issue, use RightMark CPU Clock Utility like I do...
When the CPU isn't needed (adjustable), it runs my dual core down to 1.1Ghz and 1.1vCore automatically, and it speeds up in steps, when needed.
Just be aware, if you decide on using PCI (or PCI-e) audio, stay away from the M2/M4 PSU's...