I posted an answer about the 17" LCD in the other thread.
Sony has had a 17" LCD Pentium M model out for awhile (but priced over $2500).
The Pentium M cpu will give you the best battery life, a performance comparison of 1.5-2x its mhz speed in comparison to a Pentium 4M cpu.
Also, the Pentium M notebook will be lighter than its Pentium 4M counterpart as less space is needed for the cpu cooling -- Pentium 4Ms run very hot and are really only intended for desktops (called Pentium 4 there - Pentium 4M has some power saving features but not much)
Just keep in mind that a 17" notebook will be very bulky and heavy to carry around unless it is the amazing Apple 17" powerbook at 6.9 pounds (but also over $2500).
You can still fit a 15.4" widescreen or 15" square in a notebook backpack but I am not aware of one for a size larger than that (but there are satchels of course).
But if you intend to use it mostly at home or work and want the superior battery life (to use wi-fi unplugged) it will be better than a Pentium 4M. And, you will still have the 128mb dedicated video option not available in most Pentium M notebooks.
The only thing you really lose versus the Pentium 4M is hyperthreading but that is negligible unless you are running multiple programs heavily all the time.
The 2mb L2 system cache (on the Pentium M chip itself) is one of the reasons the Pentium M can run much faster than its mhz speed in comparison to a Pentium 4M.
If you happened to check Dell's website you would notice that there is a new model out. Released Tuesday, this model is Dell's only 17" laptop! Not only that, you can customize it with an amazing array of options, including a fast 7200 RPM HD and a dedicated 128 MB graphics card. The laptop also uses a Pentium M processor.
My question is this. With all those nice options and the 17" monitor, what can expect to get from a Pentium M 725/735/ etc. processor? Will my processor keep up with the rest of the laptop? Feel free to check out the specs and reply. If anyone can comment on a laptop with similiar specs it would be appreciated. Thanks.
MO

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic