I have a late 06' MBP 15" low end model, CD2, 2 gig ram, 120 HDD. I feel that I am in dire need of an upgrade as I am getting into photography and need a bit more power. Also i am done college and making more money with all the free time that would normally be used in classes. 4 years seems a lot for me even though it is still kicking pretty well. Hopefully a new design will be in the works as well. So with that said, How often do you upgrade to a new MBP?