My top windows feature is well known to be remote desktop and has been since XP came out. For this spot there is no competition. The number two spot however has changed from time to time. This week I'd have to say the position goes to System Restore. System Restore has saved my bacon more times than I can count. This week equals count + 1. When in the course of extreme machine hacking, you break something big time, it's nice to know you can just roll back to the last known good configuration. Sometimes I wish my life had a feature like that.