windows vista 32bit, 64bit??????????

well i thought i knew everything but i guess not. i've got almost all of my computer picked out and now i'm looking at operating systems. i was on newegg and i see there's the 32 bit windows vista and the 64 bit windows vista. what's the difference?
i also see dramatic price differences. example: windows vista 64 bit home premium for system builders 3 pack DVD is $314. then there's the same thing expect 32 bit and 1 DVD for $111.
then i see a vista user license for $209
lastly i see, which is what i think i need, windows vista 64 bit home premium for system builders single pack DVD for $114
what's all this about? which one do i need?
_________________
bat control free windows registry cleaner

This all depends on your CPU. 64bit Vista will give you let you go over 4GB ram. For 32bit you cannot go over 4GB. Most programs are written in 32-bit so performance wont really matter until more 64bit apps come out. 64bit Vista runs a bit faster than 32 because the code is optimized. Most new processors coming out are 64-bit native and are running 32-bit in a compatibility mode. The next Windows is rumored to require 64-bit processor. If you use Windows Vista 64-bit you will probably never have any problems with 32-bit programs but you need to make sure that 64bit drivers are available for your accessories. So far most companies have been good with this. When XP 64 was released very few companies supported it

Vista 64 also has a kernel patch protection layer.

Kernel Patch Protection: Frequently Asked Questions

If your gonna use Vista 32bit you might as well stay with XP.

My 2 cents