You'd get an even better performance-per-watt/performance-per-area ratio using Core 2 Quad CPUs. 2.4Ghz models are available at a very nice price right now. I'm going to build a whole new system soon with fancy graphics card and all for under $1500 (actually more like $1200, including tax). If you went with onboard graphics and multiplied the number of CPUs and motherboards by 4 I think you could still be in at $2500 or so, matching the cost of that beast, but with about 4x the performance.
- Oshyan