I seriously like Vista, you just need a machine that can handle it. I also like Wubi because you don't need to partition, and it works flawlessly with Vista.
This is Ubuntu installed by Wubi. Just click Install, fill out a few questions, it downloads Ubuntu, then you reboot and there is a normal boot menu to select Ubuntu or whatever flavor of Windows you installed Wubi from.
Boot to Ubuntu, it installs, runs right out of the box. BRILLIANT. Then, reboot, choose Windows, once in Windows, just uninstall Ubuntu like you would any other Windows program.
No mess, no fuss, no partitioning, no boot loader (GRUB Etc.).