that's not a bad system.
i'm going to be putting together an A64 system very soon, too.. here's what i'm going for, and i think it would beat yours..
Generic case (I like to mod my own)
Forton 530W PSU
A64 3400+ DTR (ClawHammer core)
DFI Lanpart UT nf3 250gb (awesome for OC'ing)
OCZ pc4000 Gold ram (also awesome for OC'ing)
xp-120 + panaflow fan for cpu cooling
this baby can easily run at 2.6ghz at nice, low temperatures.
if you're trying to budget yourself somewhat, don't go socket 939. get 754 with nice ram and OC it a bit. the winchester core processors make nice overclockers, but so do the socket 754 clawhammer core processors. the clawhammer also has twice the l2 (1mb vs 512) but it doesn't matter that much since they both have the built-in memory controller which works very nicely. the clawhammer is made for DTR (laptops) so it runs nice and cool, a big plus for overclocking the system.
754 is less expensive and you can make the system run faster than a more expensive setup.