The free version of Avast! antivirus has long had a software updater module that works rather well. It handles updates for Flash, the major archivers like 7Zip and Rar, and a number of other regularly updated things — seamlessly, in the background. I’m not sure how comprehensive it is, as it may not cover major apps such as an office suite. But then, I would usually rather deal with things like that myself, on an individual basis.