My 2.0 Core Duo 15" MBP is still fine for what I do. If, however, I leaned more in the graphic design work direction, I would want a 17". Still, the #1 productivity enhancer for getting real work done is a larger screen, and no where is that more important than with graphic designers running Photoshop or editors running Final Cut Pro on video projects. Mighty nice for audio engineering as well.
The latest 17" MBPs now have true HD screen resolution, which is great. I can't imagine they'd go backwards on this with a redesigned black bezeled version. After all of the incessant whining about it, I am sure that an "anti-glare" screen will at least be a BTO option for the upcoming 17".
We'll see.