If you want that your laptop be compatible with Windows Vista, you need the x64 bits intructions sets. Only the mobile AMD Turion 64 has this intructions set. It's a very nice mobile processor with a low battery consumption, but the mobile Intel Pentium M processor take less battery power than the Turion but this last delivers better performances as I saw in some benchmarks.
For your GPU question, both Intel and ATi integrated graphics chipset are compatible with Vista. But the ATi Radeon Xpress is much and much better than the Intel's chipset.
A dual-core laptop is too much for you. Think that you'll use only the 1/4 from the total performances of the dual-core. A single core is a better choice for your use. Don't take Sony laptops. They are too expensive for nothing. Sony laptops are made for mobility and workers ( they only weight a little 3 pounds ! ).
Think to take 1*512 MB of memory for future upgrades.
The Compaq Presario v2000z is probably the best choice you can make. This laptop is for students, but your utilisation is like a student. I'm 14 and tomorrow, I'll buy my Compaq Presario laptop. I did many research about it and it seems like the best quality/price ratio.
I am buying my first ever laptop. I travel overseas a lot and will mostly be using the laptop to connect to Skype to call back home cheaply. The laptop will also be used for web surfing, e-mail, and some gaming by the children on vacation, but not much else.
I also want the computer to be Vista compatible when Vista comes out in the Fall. I like the security upgrades that come with Vista. What gives me pause is that the laptops of today all seem to have integrated graphics chips, and I am not sure how well those will work with Vista. Will Vista require a video card separate from the main board, or will a powerful integrated video card suffice? I've looked at two computers: 1) Sony Vaio SZ110 with a NVIDIA GeForce Go7400 graphics card and 2) HPdv1000t with a Intel Graphics Media Accelerator 950. I know the NVIIDIA graphics card is better, but will it be good enough to fully run Vista? Any advice I would appreciate.