trscsaeg, Secunia does this for security patches and also for a lot of applications.
FileHippo has a tool to scan the computer and show the updates available (can monitor in background also).
For addons, generally I'll set them to be automatically updated, so, on next browser restart they would be there installed.
Well, at least could be the alternatives until Comodo release something in this scenario
the last time i used secunia it was somewhat difficult to update or maybe patch is the more appropriate term idk. to patch photoshop, it wanted me to go somewhere, idr and download this file (idr the file type) and put it in some folder in the photoshop folder.
also it directed me to some part of the java site to update some part of java and the page was saying something about end of life and provided nothing to download or instructions to fix the vulnerability. that may not have been secunia's fault but the last time i used it, it just took you to the page to update whatever instead of downloading and installing it it's self like i'm suggesting cpm do
also on the 64 bit version of java, there is no update tab to configure java to automatically download java updates or to notify that there is a new version of java available. the only way to find out if there's an update is to use IE and visit the java site. if you could tell me of a way to configure 64 bit java to automatically download and notify me that updates are ready, it would be greatly appreciated.
also plugins for firefox don't notify you of updates and currently for some reason firefox 4 doesn't provide a link in the plugins section like they did in 3.6 to go to their plugin check site so you just have to bookmark it and check it from time to time. plugins such as real player, firefox doesn't know if their are new versions. so you have to open realplayer and check from time to time if there's updates. right now firefox only checks for extension updates.
do you know of a better update manager to use then secunia