That depends on what you do with your computer. Think about it, web browsing depends on the speed of your internet connection not the CPU, GRU or HD (SSD). If you use MS Word or Excel for business, again even a 3 year-old C2D 2009 MBP is much faster than the operator
!
However, if you do highly CPU-intensive related tasks, video encoding, 3D rendering or Video production, get the latest model MBP or MP and you can cut the time involved by half or more. Apps like Handbrake etc. benefit from having more cores to work with. How about a BTO 12 core MP ?
However, the occasional use of these tools probably doesn't justify the high cost of an upgrade. I would love to upgrade my trusty 2009 MBP for a new MBA, but I just cannot justify even the relatively low cost of that computer, and the older models have their advantages too, firewire CD-DVD drives, etc.
One of my friends is waiting for his old 2003 iBook G4 to die so he can buy an MBA (he actually has more than enough money to just pop for one), and the thing just won't kick the bucket!
If you can justify the purchase, go for it, if not enjoy your good'ol MBP
Another friend recently bought a new battery from OWC when his 2006 MB battery died, now he gets more battery time than the original! That's another good option.
