Hello friends i'm new here on this amazing forum ;] wanted some tips about upgrading my machine, as i'm choosing carefully every step so i do not regret anything later (paranoid mode [on]!)

I'm buying an Evga 680i Motherboard and a QuadCore q6600 2.4ghz processor (i intend to overclock it to 3.0\3.2ghz). I'm kinda lost in which memory kit i should buy for this pc though, i intend to use it heavily for music production. I'm thinking about 4gb of ram but assuming that i want to use win xp 64, should i buy 2 kits of 2x1gb or one kit of 2x2gb? which would be more efficient on this platform? i don't know about good brands\latency issues with memory unfortunally, i'm lost on the subject. I know there are these OCZ kits out there and they say that the Mushkin kits (i think that's the name) are the really fast ones. Well that's it for memories.. and now to:

Compatibility: Will i have issues with some vsts and ableton live itself using win xp 64? i heard somewhere there's a software or driver that could allow to use 32bit vsts on an 64bit platform, don't know if it's true though..

Perfomance: i know ableton supports multi-thread operation, but how good can it be.. will it use an quad-core processor properly and really give that big boost?

thank you