My rig:
QX9650 @ 4.6
4gb of ddr2 OCZ ram @ 1150mhz
EP45-DQ6
Auzentech Prelude
4x X25-E in R0 on LSI 9211
750gb WD for storage
ATI 5870
A very light windows xp x64
Everything I do not need is disabled in BIOS.
Latency is at 14us @ the median point.
My friend's rig ("aintz" on this forum):
E6700 ES @ 3.0
Asus P5W DH Deluxe
4870
4gb of crap ram
2x 74gb raptors in R0
Full version of windows 7 ultimate
No tweaks, no disabling things in bios, no nothing. Standard rig.
Latency very similar to mine.
edit: Napalm has a pretty similar rig to mine. I bet if he runs it he will also see low latency.