I used the 'Previous Version' feature to go back to v 1.4.27.0.

I've never, ever ever ever, complained about a patch. Working in IT, I know it can be difficult to please the masses, but 1.5 was horrific. The shadows on my game made it unplayable. It looked HORRIBLE. Screen flickering everywhere.

So glad I was fortunate enough to have this feature. Now that I am in offline mode in steam, I will not be updating again until whatever patch comes after 1.5 gets rave reviews.

I put previous versions on my usb key as soon as a patch arrives. So far I have 1.3 / 1.4 & 1.5

Are the .EXE's all that are required to backup? Or do you save the entire folder?

You should be able to tell from the date on the files.

Depends on the patch and the changes made --- many also include changes to the various BSA files (any mesh or texture changes) or the various other folders like sounds, scripts, etc. and also the configuration files, Update.esm and Update.bsa, etc. etc. -- so safest to back up the entire folder if you think you might want to revert.