It isn't hard to use an optimus card with Debian or most other distros nowadays you just need to install bumblebee (wheezy-backports for debian) with that you get improved battery life.

I personally don't get GPU drivers breaking the computer but I don't use nvidias drivers I use nouveau but I also use Debian so a distro like Arch (which is more prone to packages breaking systems) might be much worse.

Well make sure your hardware is supported on the kernel you are going to use, this is where debian tends to lag behind with its stability.

Try looking for people running your expected hardware with debian online and you'll probably get a better idea.

Unless you don't mind using updated kernels, most thinkpads should work reasonably well.

This should help too: http://www.ubuntu.com/certification/desktop/make/Lenovo/?cat... (Precise is close to wheezy kernel).