Let’s say you have installed your windows on the C drive, and you have an extra D drive in your computer to save all your data (setups, pictures, …).
You can buy an external drive to make a perfect backup, let’s call it the E drive. Here are the steps:
Image of your windows installation
Make an image of your windows installation -C:\ drive- with ghost, acronis or whatever and put it on the D:\ drive
Make a list of everything you have on both C:\ drive and D:\ drive
You can do this with a batch file, like this one:
cd D:\folder\
dir C:\ /ogn /s>ListeverythingCdrive.txt
download the file
Backup your data to an external drive with synctoy, syncback or something else:
1/ Backup the most important folders from C:\ to D:\ (for example the C:\users folder in vista and seven)
2/ Backup most important things from D:\ drive to C:\ drive (for example in C:\importantbackup) -> this could be the pictures you never want to be lost 
3/ Backup the whole D:\ drive to an external E:\ drive
You’re done 
Ps: please contact me if you want more information of backups or if you want a specific backup made for you
