No way... HP/Compaq sells the 2.0 for $400 more than the 1.6 Dothan but even that is not worth it. Get the 1.6 or the 1.7 (about $125 higher than the 1.6 if ordering custom) but the 1.8 and 2.0 are not worth the price difference right now. Use the money on a faster hard drive, more video memory, etc.
HP will be introducing a preloaded Linux model soon (announced at the end of July).
If you go to www.X1000forums.com (Compaq X1000/HPZT3000 Pentium M notebooks) you will see an entire Linux area --- Someone there has written 2 custom free Linux versions just for these 2 models --and the 3rd version will be posted soon. This forum is full of people discussing how to get the wi-fi working, etc on a daiy basis. That is a huge selling point for these 2 models if you are interested in loading Linux
Is it worth spending about $600 more to get Intel Pentium M Centrino 2.0 to 1.6?
Lets just say I'll do almost everything. From just browsing through websites to creating 3d animation, and programming.
Also, do you know if Redhat Linux works fine with notebooks? Notebooks seems that they really prefer Windows XP.
Thank you.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic