opposite of unbuffered is registered RAM which is only for servers platforms like Socket 940 so unbuffered is what you want of course.
Also, does anyone know about the Corsair XMS Dual Channel Ram?
What about it exactly?
If you don't plan on OC'ing corsair is fine....if you want to OC then you should get something like OCZ Platinum Rev2's, they are pretty cheap right now, however they use Samsung TCC5's not instead of TCCD's which are SUPPOSED to be just as good, but theres an on going debate about that.
Patriot XBLK's are brainpower PCB and Samsung TCCD's so those will OC nicely
But if you aren't going to OC then hell you might as well get valueRAM, you won't notice a difference in performance between 2-2-2-5 timings and 3-3-3-8 timings when you're using stock speeds....you only want 2-2-2-5 so that you can OC the hell out of em.