This is actually an involved question... I don't think there is any such thing as a "best" system, just the right set of trade-offs for what you need to do with your computer.

The first step to ask is how do you intend to use it and how portable do you want it to be. I travel quite a lot and I go with lighter laptops with smaller screens because I'm 6' tall and on planes I always sit behind someone that likes to recline. Smaller 'road worthy' laptops are also a lot easier to lug around. If you are using it for shoots and plan to pack it with a bunch of other equipment you might want to go with a larger desktop replacement type model with a widescreen.

Regardless I'd go for the newer Intel dual core processor and 2GB of RAM. I tend to stick to Dell and Lenovo (was IBM Thinkpad) because I've had very good luck getting repairs when I'm away from my home base and they are very good about making driver updates available more than a year after they stop selling the product (IBM was especially good about this).

Pay attention to repair/warranty stuff, if you buy a high-end system AND you plan to travel quite a lot I would definately buy an upgraded warranty (this is only occation I make this recommendation). Sh*t happens to portable electronics, I expect a laptop to last me at least 3 years and the odds that you'll need some sort of repair are medium-high.

This is my .02 cents, non of this may apply to what you intend to do though.

Best of luck!