Nothing beats the centrino when you really need Mobile use. The turion is just selected A64 chips that will run at lower voltage thus consumming less power and making less heat. Centrino (lets call it a Pentium-M now, centrino is the whole chipset with WiFI) was designed from the ground up to be a mobile CPU, so it includes all sort of feature to limit power consumption and a heat output. Youc an google for review from toms/anandtech etc if you want more info on this subject.
I personally have a 1.7ghz 2mb of cache Pentium-M laptop and I really liove it. It weight 4.2lbs and batetry last for 4h+. Im also a student and being able to carry your laptop for the whole day really is a +!
If you dont mind about 64bit, Pentium-M is the way to go
Asus P4P800DX, P4C 2.6ghz@3.25ghz, 2X512 OCZ PC4000 3-4-4-8, MSI 6800Ultra stock, 2X30gig Raid0