What type of backup do you want? For me, I keep everything on a server. And my server has 2 drives, which I sync together every few hours using robocopy at the command line in a batch file.
Then every week or so, I plug in an external drive and run robocopy and sync the data on my hard drive with my external drive. In addition, I have another external drive that I sync up as well and keep off site in case of robbery or theft.
For my OS on my workstation, I like to run Acronis True Image and just image my C drive onto my D drive right after install and then every now and again so that I can get back to where I was pretty easily. Mind you this is mostly just applications and patches...as all of my data is stored on my external USB drives.