Mh... I don't think that the MPBs will get 45nm chips already in January. As far as I know most of these 'early' Penryn chips yet have an 800MHz frontside bus AND require 35W juice -> no significant advantage over the Merom and much higher cost.
It's a lot more likely that the current Santa Rosa MBPs will get a slight speedboost. 800MHz RAM, 256MB/512MB VRAM, 'faster' CPU 2.4GHz/2.6GHz... this is realistic, no big changes though but still making the MBPs a bit more perfect.
Again - if they upgrade the MacBook to a Santa Rosa platform, the MBPs WILL receive a boost too or they will simply get too equal!
It's true that the Intel GMA X3100 is a proper videochip but
consumers want to play games also. Especially the student bunch who are into Second Life stuff and World of Warcraft - this brings whole MASSES to the MacBook. I'm convinced that we will get dedicated graphics in the new MacBook. Dedicated graphics with a 128-bit memory interface because otherwhise it would be pointless and the most suitable mobile solution yet is the 8400m GT.
Well, let's wait and see. *shrug*