Best system restore application/method in Linux
I am very experimental with my Debian machine also i am very fond of stability. Thus i tend to try new packages and new configurations in my machine, which often breaks my machine or make it slow/unstable/buggy. Thus i was wondering is there any tool/application/method to restore my system to a fixed stable point i want.
Assume, On 1 Jan 2013 i have my best stable configuration of my system, and i somehow stored that machine state somewhere by some application/method. Now, on 01 July 2013 i feel my machine is not stable enough and want to revert back to original configuration of 01 Jan 2013, including removing all new packages, reverting back all config files changes, and everything.
So what i need is that METHOD/APPLICATION capable of doing so.