It would be very cool if Microsoft and other operating systems would allow you to configure permissions for each executable and what they can access in the system (if there is not a way to do this already).
For instance, I just downloaded some code from some guy I never met that had something I needed posted in a newsgroup. The guy's been on the newsgroup for a while but how do I know he's legit? He sent me exe's not source code so who knows what's in that - but I really need this little functionality because it will save me a ton of time.
So anyway, I'm sitting here debating if I should use this thing or not and that's when I was thinking it would be really cool if I could just right click on this little exe and set up permissions for it - whether or not it can access the Internet inbound or outbound - specify which IPs and ports it can access for some internal testing I need to do with it (is related to TCP/IP and sockets). Additionally I would like to be able to specify which user accounts it can run under and what directories and files it can access - and whether it can read/write/modify/delete those files or in those directories.
It would also be nice if I could set my default permissions for new files and executables and then alert me if some exe or program of some sort is trying to access something for which it doesn't have permission and let me decide if I want to give it permission or not.