File sharing program?

I'm curious as to what it is people "share" files with. Such as MP3's, videos, files, pictures whatever. I used to use LimeWire but I have been having issues with it lately connecting to their servers so instead of trying to fix my clientside problem i'll just change to something else and remain lazy.

Just curious. I know there are still some older popular ones like Kazaa out there, but not exactly sure what everyone uses.