Single PC:

i7-920 @ 4GHz
12GB Corsair 1600MHz RAM
ATI 6950 2GB
Corsair F115 SSD (Read = 280MB/s, Write = 270MB/s 50,000 IOPS)
Win7 64bit Home Premium
2 x 24" Displays (1920x1200)

5 Boxing with IS Boxer and have all 5 clients on the same settings - High with shadows dropped down to Fair, as they seem to have the biggest impact on my system in Cataclysm.

Runs like a dream