I'm poised at the brink, ready to switch from PCs over to Macs, and the more I ogle the systems the more I know I want to shell out the cash and revel in the glories of Tiger. I've already racked my brain with the iBook/Powerbook and 12" / 15" decisions, so I won't be boring you with that minutia, but I just discovered another factor today that I wanted to throw into the mix: noise level. Currently I have a PC notebook (an HP) that I used as the hub of a bedroom recording studio -- nothing fancy, just an external card, a few mics and an acoustic guitar. But lately I'm becoming frustrated with how loud my notebook fan is -- don't know if it's loud enough to pick up on recordings, but loud enough that I'm worried about it now. I'm 90 percent set on a 15" Powerbook, but I don't know how loud the system is when it runs because the Apple Store near me is always loud and busy. So: what system would you suggest if silence was a factor in buying? I'd prefer to stay portable, but I've heard the Mac mini is crazy quiet. Are the PBs quiet enough that I won't be worried by them? Input requested.