Its all depends on your budget.
you should ask yourself…. What do you need from your notebook?
If you want to be mobile and battery life is important to you, I agree go with the Pentium M (Centrino, Donthan). But, if you want to go that way, I would recommend waiting for 2-3 months because Intel is going to release their new mobile cpu (the alviso), which will cause a substantial price drop for older models.
But, if its performance you want…. I would recommend sticking with the desktop cpu.
I myself have one of those machines, I used to carry that monster (5KG) to work everyday, but it was all worth it.
Again, if you want to take your notebook to a LAN party, or simply to enjoy computer games in your bed: get a barebone notebook form ECS or Clevo / Sager and simply build it according to your needs (that of course if you know what you’re doing). You might as well try one of the Sager notebooks, they are not bad, and basically they are the same as Alianware, Same cassis, same components for much less money.
http://www.sagernotebook.com/pages/notebooks/product.cfm?ProductType=9860
this one even has a pci express. (radeon models also available)
As for other brands, I would recommend against buying a Toshiba, I had a bunch of 'em, and to tell you the truth, they were bulky and not very features to dough friendly.
Whatever you do, NEVER BUY DELL. I have the scars to prove it.
IBM's are not graphics friendly (besides IBM are selling their PC business, so you dont know who you'll get as the supplier in the future)
Acer's: way too overpriced. Especially their Ferrari notebook.
as for HP, don’t even go there, they make the most crappy notebooks out there with the cheapest components possible (right after dell)
Sony: if you are considering a thin and light… yes, maybe. otherwise they are way too expensive and bulky, simply stick with Fujitsu if you must buy Japanese.
I never had Asus, so I cant really say, I do however recommend ECS, the G736 is the best notebook I ever had (and I had more then 30 notebooks in the past 2 years)
the best thing about ECS is that thy sell them barebone, so you can add your own hand picked components.
anyhow, good luck.