I've always been an intel guy, but I just bought a brand new AMD64 system specifically to run all my synths and soft samplers. It's an Athlon 3500+ with 2 GB RAM on an ASUS A8V Deluxe mobo. 80 gig system drive, 250 gig SATA drive for the samples. I've just started really putting it through its paces over the last couple days, and simply put, it's amazing. MY first AMD system, and it won't be my last.
Can't wait for XP 64-bit and Sonar 64-bit so I can REALLY see what this thing can do...
I have an Asus A8V-Deluxe with an A64 3000+, and it rocks. I can run almost twice as many GigaPulse instances with it compared to my Athlon 2500+.
Here's a warning though... Echo cards don't seem to get along with the A8V-Deluxe. My MIA would blue screen the system as soon as the driver loaded. I RMA'd the motherboard and it happened with the replacement as well. I'm now running an Audiophile 192, and it's fine. (My kids get the 2500+ and the MIA. Lucky brats. ) Hopefully Echo will release a new driver, or VIA a new BIOS that will fix the problem soon.
I'm a convert from Intel to an AMD Athlon64...very similar to Steve's machine.
There is quite a bit of discussion on various forums about AMD vs Intel. Try typing the following into Google:
"Scott Reams" AMD Intel
with the quotes, and you'll see what I mean. Scott's quite well respected in the SONAR forum for his deep technical knowledge, his experience as a recording engineer, and his musicianship.
The AMD Athlon64's and Opterons seem to have the edge over Intel in audio recording, according to the benchmarks I've seen. Best to do a bit of reading on this.
I've got an Athlon64 3200+, K8N Neo with NVIDIA nForce 3 250Gb Chipset, 2GB memory, separate 250GB SATA drive for the audio, an EMU 1820 for sound. Plus a 21" Apple Cinema Display (which has nothing to do with Intel vs AMD), but a good display is one consideration in a DAW, particularly when you consider how much real estate you can eat up when you've got the score up and you're dealing with a number of synth instances.