I was considering going with a 17", but really.. whats the point? A laptop is meant to be mobile.. 17 inches is fucking hudge, and heavy. 15 is pretty big, but its manageable. A 17" laptop on a airplane tray is not happening.

I went with vista when I got my laptop a year ago, idk.. I think its fine. Windows 7 is probably fine too. Youll get used to either in a few days at the most.

Id definitely upgrade the battery, and upgrade the processor as far as your budget will allow as PT3 and HEM, while much better than the first iterations of PT, can be resource hogs.