I have had a dell 9300 inspirion for a few weeks now. I am very impressed with the performance.
It runs very fast.
It runs for hours on a battery & the 17 inch screen has come in much handier than I would have expected. I initially intended to use dual screen most of the time but have found myself not bothering to connect up the second monitor.
The graphics card makes a big difference with 3 d transitions & effects in boris etc.
Specs
2gig centrino 533bus
1gig ram 533
6800 geforce PCI express graphics
7200 rpm system drive
7200rpm external firewire drive (connected into firewire port on laptop)
vx2000 camera (connected through PCIMA card)
If you want a laptop that runs cool & fast &b long this is the one.
I am sure you may be able to get a more powerful P4 laptop but be warned they will not last very long on a battery.
Also Alieen ware have some killer laptops with some very big batteries.