I have been using CloneZilla to manage all my disk and partition backups, I find it very user friendly and support all my disks (USB, ESATA). I recommend TUXBOOT for making Clonezilla bootable USB drive and to keep it with you whenever you need to clone a disk, then just boot off the stick.

http://clonezilla.org/liveusb.php

Windows 7 bootable USB stick

On the subject, sometimes you need to get an OS on beforehand for Windows, I like using this tool to make a bootable windows 7 USB stick.

http://images2.store.microsoft.com/prod/clustera/framework/w7udt/1.0/en-us/Windows7-USB-DVD-tool.exe