I have the os and all applications on one physical drive without anything else on that drive. All my data is on a different physical drive, which is also partitioned. For example, I keep my iTunes library on a different partition, and I don't back that up every day. This setup is really convenient for various reasons. I can physically switch out a data drive in just minutes. (This is non-RAID.) But performance is not that great. With large drives being so cheap now, should I just put everything on a single drive and include the applications in my backup schedule?