Now that I've had this 2GHz MacBook Pro for about a week, I thought I'd put down my impressions as someone who went from a PB17. Both machines had 2 GB RAM, 100 GB 5400 rpm HD.
Background: I really enjoyed my PB17 over these past 3 years. It was truly a replacement for my Pismo (there was a TiPB in between, but that machine had some major compromises like poor Airport reception). The machine's extra width made it more comfortable to use compared to the TiPB for me (I'm 6'2"). It was, however, underpowered from the beginning.
Review of the MBP: I concur with most of the positives voiced around here and elsewhere. Great screen, very fast with universal apps (especially Mail), acceptable occasionally running photoshop [you won't confuse PS performance with a dual G5 desktop], and M$ word is ok. I have not experienced (yet) any of the problems that appear to be restricted to a small minority of these machines.
Comments as upgrading from the PB17: I considered waiting for a PB17 MBP. But for much of my work, speed has been a bottleneck. Here are my surprising findings:
1) Both the MBP and all but the latest versions of the PB17 have screens with the same resolution - 1440 by 900. The screen is physically smaller, but there is the same amount of pixel real estate. That has been a seamless transition. Until I put them side-by-side, I have not missed the larger screen.
2) The size is fine. It feels more like a PB17 than the flimsy TiPB. Just as going from the Pismo to the TiPB resulted in less weight in my work bag, both the PB17 and the MBP are fine machines for carrying to and from work on a daily basis. The less weight is good, but the extra weight or size of the PB17 was not a deal-breaker for me. [If you want portability, I still think the PB12-style machine is the way to go].
3) If you do any complicated work in powerpoint, do consider purchasing iWork with Keynote 3. That is MUCH faster than powerpoint running via Rosetta. Like the Mail app, Keynote on this machine is a real 'wow'. Movies load without a wait.
4) The FW800 port is the only functionality I'm missing that I did occasionally use (the other changes have been discussed in detail elsewhere). But in fact, I've gone pretty much solely FW400 this past year, and none of my other machines have FW800. If you need it, there are FW800 cards in development.
5) The battery life is fine, at least as good as my brand-new replacement PB17 battery.
6) Airport reception is very good, at least as good as the PB17.
Conclusion: For those considering an upgrade from a PB17, I think owners of all but the most recent PB17 models will find little to fault in this machine. Apple will probably make a MBP 17 model, and it may be great. In the meantime, if your work productivity (like mine) was hampered by the many waits of spinning beachballs and universal software is currently available for your needs, you may find the MBP a capable machine with surprisingly few compromises in reality.