How big is your mac? (and other computer looping questions)

[Philip <toejampc@gmail.com>]

After getting inspired by Kid Beyond's vids, I decided to get a copy  
of Ableton.

I'm curious about what Macs and configurations people are using with  
their computer looping software.

I've had Logic freeze up and crash on me when I was using it on a  
Macbook, so I wouldn't trust it for live stuff. I'm thinking of  
getting a one or two year old 15" or 17" MBP, maxing out the memory,  
and not putting any software on it except for Ableton.

Is that being overly cautious? Will it matter if I put Mail MSOffice/ 
Firefox on it provided I turn them off when looping, or does simply  
having them on the machine use memory?