4Shared makes you wait 20 seconds to get a download and opens up new browser windows from here.
DropBox creates a Public folder that you store your shared files in. They back them up so that you can immediately get access to them from anywhere. Install DropBox on another computer and log in and the other computer has your Public folder and everything else instantly!
It also doesn't make tou wait for a download and you can post pictures to display that won't be downloaded unless you zip them. If anything should happen to your computer, all of the files are safe too!