Speaking as a fellow audio geek (with a recording rig):
An SFF that supports two 3.5" HDs may very well be an interesting option for you. Why?
A) If you are going to do multitrack audio recording on a laptop, don't expect to do it on a 2.5" laptop drive. Regardless of how nice your DTR laptop is, you MUST have a fast external HD to support multitrack audio recording. Why? Well... a 2.5" HD dedicated strictly to audio recording probably has enough bandwidth to support a few 24/96 channels, but once you factor in the swapping of the OS to the HD and other such issues it becomes dicey in a hurry - I'm talking audible drop-outs, clicks, pops, etc. If you want 8 or more 24/96 channels reliably, in my opinion it is ESSENTIAL to have a dedicated hard drive.
B) once you have that much to carry around anyway, why not go a little larger and get something with the speed and expandability of a desktop? PCI-based multitrack audio recording systems (e.g. M-Audio Delta 1010) generally have as-good-if-not-better audio quality and are
substantially less expensive per audio I/O port than USB- or firewire-based cards of the same level of capability (e.g. M-Audio Firewire 410 at $500MSRP vs. more-capable (8 analog ins vs. 2) Delta 1010LT at $300). As for speed, don't forget you're going to want to run plenty of plugins (eq's, filters, flanges, reverbs, etc). Some of these plugins are going to be floating-point instructions too, which is definitely NOT the P-M's strength.
Frankly I don't personally care whether you go Intel or AMD. In my own experience, Intels are a good choice, NOT because they are faster (which they are not), but because the chipsets are the industry standard for PCI compatibility. NV does a good job on the NForce from what I hear, but when in doubt, for a music system, I'll still go Intel -- specifically because while the processing power is nice-to-have, a click-and-pop-free system is downright essential. Back in the "bad old days" of VIA KT133, KT266, etc., I knew many an engineer who assembled an Athlon system and simply couldn't rid it of click and pop problems no matter what they did... I'm not saying that's a good reason to stay away from NV now - I haven't personally experienced problems with their chipsets - just pointing out that Intel continues to set the industry standard for chipsets, which is what matters the most when trying to avoid click-and-pop probs.
Whatever route you go, I strenuously recommend the biggest, highest-resolution screen you can afford (another benefit of SFF: dual DVI outputs). Believe me when I say it is simply delightful to have your mixer panel and your editing screen up at the same time. If you're running MIDI sequencing, Plugins, Reason, VST/DX instruments, etc. it consumes screen space in a hurry!!!
Hope this helps. Feel free to private-email for more discussions (I don't get much time to pop by this forum) at
eris23007@hotmail.com
Jacob
P.S. Music programs don't always update that quickly to new tech. They tend to be more concerned with continuing stability. Therefore I am of the opinion that 64-bit is not a major concern in your implementation, and frankly I'm far from convinced that it will be useful/relevant in the near future. Remember, when recording, stability is the NUMBER ONE concern.