I am using Dua-Core on regular Home and Professional. though I was thinking of 64-bit as well, but the minus points of 64-bit O/S are:
you wont be able to find all hard-ware drivers for 64-bit.
and, some 32-bit applications runs slower on 64-bit os. better to get sp1a+ so you'll get dual processor support, otherwise Home only support 1 processor. (not the case in xp-pro)
Intel Core2Quad 2.66Ghz 12MB L2-Cache
4096MB DDR Kingston Hyper-X
XFX 9600GT AlphaDog
Seagate 2 X 320GB SATA2
LG L246WH Flatron 24"