I'm not really impressed with this update (because I was hoping for a revision). I'd say the most meaningful thing is the GPU, which is nice for people who play games or do any sort of visual editing. I was hoping that the 2.6 would be standard for the high end, but alas no... still gotta shell for the BTO option. Also because the only thing that was bumped was the CPU speed (kinda) and the L2 cache, I'm waiting for Montevina (and hopefully a case update). If I wanted the ones out now I would just by a 7 month old one off ebay, which would be pretty much just as fast as these 'updates'. Here's hoping they don't find a way to make Montevina just an update.
One word "Heat". The lack of 100+ degrees on your lap and needing an external cooling device justifies the new MBP. IMO