hey upgrading my cmp questions =)

hey my current rig is

x2 3800 oc @ 2.45 ghz  am2

asus m2n-e mobo

450 watt psu

x1900 xtx oc

2 gig pc 4300 ram

aspire cruiser case

i am selling this comp and building a new comp..i was planning to get

e6400 core 2 duo and oc  it

2 gig ram...pc 4300 for free

600 oc psu

160 gig hd

i dnt no wat mobo would it matter if i get a cheap mobo like msi kn9 neo for 114 canadian??

8800 gtx

thermaltake tsunami case

zalman 9700 cpu cooler

watchu think??

and i need an os..vista or stick to xp??? hmmm