I chose Corsair for its compatibility - to many reviews on various boards dont like Patriot for my taste. Since they have the rebate, its only $2 more for a better brand, so why not?
Some things to think about -
Case - move to all aluminum, helps with heat dissipation, even if you get one with a side window to show off mods.
ABIT - its the older chipset, 955 not 965. The only guarantee for acceptance of Conroes, that I have heard, is the 965 or 975X chipsets from Intel. All of the 975X start at $200, another reason I chose the Corsair, since it is compatible with all of those as well, even the tempermental ASUS.
HDD: personal choice, mine was for the 10k and access times of the Raptor, but if you have need for large storage, many other drives will meet your needs.
RAM: Just check the manufacturer website to make sure its listed as compatible. Nothing worse than having to send it back and wait another week b/c you didnt do the research. I'm not saying the OCZ wont work, just FYI.
PSU: Get a more solid PSU, maybe one w/o lights - efficiency is the primary goal for a more solid power flow - that and (for me) quiet fans are key.
GPU: Cant stress enough, even for the games you play (as I do too), get the best card your BD will allow. The X1800 XT will run circles around the X850 and look 10 times better with the new Avivo technology. Some of those are only $230, even if its an OEM version, I think all would agree the extra $100 would be well worth it.
Hope this helps.