I've really enjoyed using my mid-2010 2.6ghz 17" MBP. I've paid so little attention to laptop refreshes and advances in processing technology since getting it that I'm now completely out of the loop. In fact, I'm surprised to see that my 2.6ghz processor looks stodgy next to today's current 1.8ghz! So let's say I can get $1200 for the macbook pro. If my goals are a) greater performance, and b) more portability (the Air looks tempting, and I'd even consider a Windows machine), where would you re-invest that money? Could be new, refurbished, or even used. Current gen or previous. (Note: I might be able to squeeze another couple hundred, but would prefer not to). Thanks so much!