i got this procie i3 3220.
i still lack these parts: mobo, ram and OS version.
i have a mobo in mind which is b75 from either asus or msi. going asus i think since msi is hard to find. (if someone can help me find this

)
purpose of this pc is for gaming.
question:
1. what ram should i get? pls help. pls specify what model and brand so i can buy one asap. also include price and store if you have info on that.
2. what os version should i get? 32 bit or 64 bit? i am currently using 32 bit windows 7 in my old q6600. should i switch to 64 bit now? if yes, why and what benefits will i get with going 64 bit. im planning to go 64 bit since im planning to get 8 gig ram. pls suggest if this is a good move or what.
tyvm

happy new year!
NOTE: i followed keropi's guide for this. tnx.