Look for low latency ram, I think the ones you have there are 3.0 search for one that is 2.5. Unless you are planning on overclocking I'd say go for DDR400 (Why waste money :-/ )
As far as budget cd-rw's go .. I suggest liteon, in fact I prefer it over most expensive manufacturers now.
Make sure the hard drive is SATA, and if you have extra money, go for another one and put it in raid. You can use an old IDE on the side for crucial data (b/c RAID 0 is suscpetible to data loss, although I haven't seen it happen to anyone I know yet)
Buy a proper power supply (450 should be nice) from someone like coolmax, antec, ernermax, pc powere and cooling. The 350 that comes with your case ... well I don't trust it.
IMO, It would be better to wait for the BTX mobos PCI express and DDR2. but if you can't wait that long, I suggest dropping to a 3200+ 64 processor rather than the 3400 which is double the cost and not much more performance.
If you are ordering these parts online, (I am assuming you are buying from newegg because I saw the exact same prices there) and you live in NJ or CA, you are screwed on the tax :-/ (as far as I know) ... as for the OS. If you have an old computer around w/ 2k that should be sufficient for now. XP pro is nice if you have the means to aquire it (which you should if you took all my suggestions)... and maybe ... even if you didn't ...
I like hte ATI card ;-) however I would also wait on that just a bit because prices are gonna fall on that as well.
So my suggestions above are applicable to your system if you are gonna buy now and can't wait. But if you have a little patience, you can get a pretty nice system within the next 3-4 months
if you can't wait 3 -4 months, wait at least 1 month because by then I htink the 9800xt will fall down in price.