I agree with your mode...
Many of my clients have files too important to back up, just to wipe and reinstall. So spending some time trying to reduce the virus probablility is worth it, before backing up these needed files. Some of them don't even mind running with malware still active on the PC, as they have no personal information on the PC in the first place; and have no data needing to be backed up. I figure it is the clients decision as long as the personal ID risks are discussed. They figure as long as the PC runs well, they can deal with the infection later.
Many times I bother to remove the malware just so I can continue to learn this; it has improved my troubleshooting skills also. I actually like doing this - however, so I can't blame IT types for nuking the drive.
When I worked as an employee on contract, our CIO didn't want us wasting time removing malware, so we would simply start over. However, we had a server image we could work with, and sometimes the individual machine actually ran better after restoring the image. This image was fully updated of course.
This way we didn't have to reinstall all application, etc. The only thing extra to do was point the clients My Documents to the network share, where their files were actually stored - unless they had a shared printer, but that wasn't too bad.
My primary mission is to try as hard as possible to prevent infection with a deep defense. This has worked pretty well, as my clients rarely need help after I get them up to snuff with the latest in security tech.
