Originally posted by vilem.krejci:

I suppose it depends on the active "Steam cloud". I recommend to switch it "off" if you don't play on more then 1 PC.

I had disastrous results playing on 2 computers with Steam Cloud enabled. It was really broken for a while there. Now if I am going to be changing machines, I manually copy the the files listed in the OP to a flash drive, and replace the ones on the second machine before I start.
I'd also add that if you're going to backup/copy those files, you should completely exit Steam before you do so. I think (but am not sure) that those files might not get written until you're exiting, much the same way the Cloud would wait until you exit to sync the files.