Yep Chrome, your right about 2 drives as the dux solution [I'd like 3 ....one for the OS and programs, one for the paging file [swap file] and one for important data and other files.
Alternatively a small USB [1G to 4G] keychain drive is a cheap handy alternative as a data backup [better than disks] and will backup a fair amount of data.

Failing the above, a partition for the OS and one for files [and one for programs if you like] is a pretty good alternative for the average Joe. Mostly it is the OS that crashes and the partition can be simply re-formated and the OS re-installed.