For more then ten years i was perfectly happy with Windows as my only operating system. I like when things improve and Windows was improved in each version. Hardware compatibility, overall stability, security, user interface: they all changed for better in each version of windows.
In case MS don’t succeed in making Vista a great OS i want to have another choice. Some time ago I tried some Linux distributions on virtual machine and now I installed Ubuntu 7.10 as dual boot to XP. Now I have greatest dual boot system I ever had.