2 QUICK QUESTIONS ON OS AND RAM

Hi there,

I have been piecing together another computer thatwil be exclusively for gaming. I have just used parts i have come across over time from other rebuilds or unexpected deals etc etc., so itsnot all of the latest and greates but I think it should suffice to run games...I think>>>>>>>>.

So far i have

NZXT Tempest case
Gigabyte UD3R Board
4800 series radeon graphics from HIS
Core 2 duo E8600 chip
Hitatchi Deskstar drive
Moaxorb EX cooler

Here is what I need to know.... I can choose either a free XP pro OS disk or a free Vista OS Disk.....which one do I install??

2. I can get 2 x 2 gig of Cucial ballistix DDR2 800 4-4-4-12 RAM at a screaming deal....but it is not on my MOBO compatibility list whereas Corsair Dominators DDR2 1066 and OCZ Golds are.....would you do the crucials or one of the others at 2 or 4 Gig.

THANKS !!

I'd go with the XP and wait for 7; I'd go for 1066MHZ, I'm not partial on the brands, both are good.