Athlon xp3000+ 64 bit processor, MSI K8T motherboard, 512 megs RAM
ATI dual head 256 meg video card
RME Hammerfall 96/52 (26 simulataneous ins and outs)
120 gig program drive, 120 removable backup drive, 2 160 gig drives in mirrored raid array
Pioneer DVD +-RW, Teac CD-RW, Mackie UAD-1
I constantly run mixdowns at 24 bit 44.1 khz with probably 32 mono audio tracks, 4 busses, 6 aux sends, and 3 or 4 vsti's with EQ's enabled on most, and likely about 30 channel strips and/or comps (on average about 6-10 of those comps would be from a UAD card). Typically on my aux sends I will run 2 waves IR high quality sampled reverbs in FULL mode (definately a CPU hog there), 1 UAD Dreamverb, a waves multitap delay, and sometimes either some other modulation type effect or vocal doubler etc...
On average, a mix like that will run about 50 -60% in Nuendo's performance meter. i should also note that antivirus programs, video card programs, and other backround apps ARE running in the backround as well as a Real Time Analyzer in my second monitor. Video Card is at high resolution as well.
My point is that the new Athlon 64 bit processors absolutely ROCK!