mahi poi no ka oi
r00ticus
The system you are wanting to build is quite a nice system. As far as suggestions I have a couple for you to consider. First of all the motherboard; ASRock *can* make a decent board but for the most part the rock solid heavy hitter is an ASUS board. Secondly, I would suggest that you spend a little more and go with a Nvidia graphics card. Don't get me wrong, ATI does make some damn good cards but you are going for an Intel build. Intel and Nvidia combo is the way to go. Now if you were going for a AMD build then an ATI card would be a good buy for it. Also that card your using is still in the 4000 series and not the 5000 series. So... for the price you can get a geforce GTX 260 or GTX275 that is price comparable and will most likely out perform that ATI card.
I've never had an ASUS motherboard. Mind giving a model as well as brand? I personally use an evga x58 classified motherboard. It works well for me. I would also say that if you're making a gaming com, a solid state drive may be the way to go. Solid states last longer and are accessed faster than hard drives. They generally have a smaller capacity, but for a gamer I think speed is more important.
I agree a SSD would be a nice add in to his build but unfortunately the prices on them are still ridiculously high because of new technology and all. So if a SSD is in his price range I would say use it for the OS and *maybe* a few most used game/progs. Then have the 1TB he chose as a storage and everything else drive. Also from my experience Western Digital drives have gone down hill in the past few years. I can't tell you how many WD's I've gone through. I suggest buying a Seagate and for the SSD, OCZ makes some great drives.
As for ASUS boards the new PT6 X58 boards are really nice and their gaming oriented PT6 X58's such as the Rampage II Extreme and WS Revolution are great. Another reason I recommend ASUS too is for thier customer support and software. They provide nice mainboard software for on the fly OC and other utilities and tweakability targeted towards gamers.