Some things :
1) Don't use DX12 class hardware with E8600... it's pointless.
Upgade to Quad Core, overclock it some and even then think about getting DX12 class hardware IF you plan to use it to browse internet (or watch videos).
2) GTS 450/GTX 460(560), or equivalent ATI late Terascale class card will all do just fine.
Lower mid-range Kepler/GCN 1.0 are "OK" if you care about power/noise and want efficient WinXP machine (Maxwell 1.0 is pushing it for WinXP, but is very good for Win7).
3) Currently DDR3 has two pros, vs. DDR2 :
a) It's usually cheaper for faster spec (depends on MB, no point in being cheaper if MBs is more expensive)
b) 2x 4GB kits that are compatible with Intel chipsets are actually available to buy without premium tax (doesn't matter for WinXP 32-bit).
4) E8600 being highest frequency CPU for platform mean highest 1T performance is simply being short sighted by numbers.
ALL(*) boards can increase FSB, sure it means you can OC E8600 as well, BUT there are games in WinXP like GTA IV that simply require Quad cores to run smoothly. Throwing driver overhead on top of that, could make some nice quality of gameplay difference (in short, for me there is big difference between "Quad cores are good enough for 1T games" and "Dual cores being fine with 4 thread optimised games" statements).
(*OEM board can't or need BSEL mod, but even then are usually limited to 1333/1600MHz)
Regardless, it's up to user to know what games/programs he plan to play/run on this. For what I know, high clocked dual core may be good for what he plans to do. Because of this, I'm simply providing some info on how things work, instead of shouting "put quad core in there immediately !"