Windows OS help

> I am building my own computer and have all the parts together execept the
> OS
> which I still need to choose,
> I have an old computer which runs XP home 32-bit and I like it but I have
> heard that it only recognizes 4 GB of RAM at the most and doesnt recognize
> the 4th GB that is why I thought that maybe I should get XP pro X64 so
> that I
> can in the future add more than 3/4 GB of RAM. On the side (obviously) I
> will
> be doing some gaming and also 3D design, unless vista can run windows 95
> programs I don't see why i should bother getting it and what about XP pro
> Sp3
> what the heck is the big difference anyways? so to the point, please give
> me
> any information that will help/aid my desision on an opperating system.
>
> My specs aside from the above yakking:
>
> AMD Phenom X4 9850 2.5 Ghz
> 4 GB G.skill DDR2 1000
> 8800 GT gRAPHICS
> FOXCONN 970 GX am 2+ motherboard
> "A case"
> 680 Watt psu
> CD/DVD combo drive
> 320GB sata HD
> and the until someone gives me a tip off the, "yet to be decided OS"
>
>
> THANK YOUOO!
>
> ps. please reply sombody
>
> p.ps pleaseeeee...
>
> p.p.ps and please dont make your coment really lame and unhelpfull
>
> p.p.p.ps thanks!