I have to disagree with some of the postings here.
The MBP is a pro machine, it is about reasonable mobile power. Some of you are talking about it being thinner and lighter in the next version. I don't think so.
The power needs cooling this ussualy means moving the heat out without frying something. Remember also that video cards are also very hot even when undeclocked.
I expect the weigth and size will remain about the same until Feb/Mar 2009 when IMHO Apple is more likely to do some radical changes.
I hope I am wrong, but I do not think we will see a thinner and lighter MBP for a while.
The wider the computer, the thinner they look. The 17" looks real thin now. Apple might just make it a touch thinner, so they can say it is, but use the wedge and taper styling of the Air to accentuate that thinness even more.
The MB will be interesting in that if it looks too good, then maybe the MBA sales suffer? That's ok with me, cuz I want an aluminum MB with the led screen and touch pad of the Air. The price difference would allow me to get a separate bigger display, time machine and some necessary updated software. Apple gets all of my money anyway. Oh, I forgot about a 3G iPhone down the road.