I just installed Windows 2000 on my Giga Pc. Got Giga running, and for kicks plugged in my Mac 120GB Firewire Drive. Not only did it come up, but Giga recognized it fine. So I got real daring, installed all my new Garritan strings on the firewire drive. Restarted Giga - and it worked. I was loading and playing it all off the Firewire drive with no problems at all. Cooler yet, I then plugged it into my Logic Mac, and used some of the gigs in EXS. So, I don\'t know if this is common knowledge, but it\'s quite a handy revelation for me. Very cool.
The drive is a generic (Western Digital 7200 cheapo in a no name 911 case). I got it from Pricewatch for like $200.
Sorry, I don\'t run audio on my PC, just Giga so can\'t really test audio and Giga at the same time.
My thoughts on laptop are that you will probably have to print Giga tracks to audio more to get around the bottlenecks. No big deal. That\'s what I do with my Ibook and Logic. Just print sampler tracks to audio earlier in the process - not a bad tradeoff for a mobile rig.