Chrome's little download toolbar is great for keeping track of how far along your downloads are, but it's annoying to close it every time one finishes. Always Clear Downloads is a simple extension that fixes this annoyance.
Always Clear Downloads is pretty simple: When a download finishes, it closes Chrome's download bar. That way, you don't waste that screen real estate (which is especially handy on small screens), but you still get to see the progress of downloads while they're happening. It does take away the convenience of accessing those finished downloads right from Chrome, but you can always press Ctrl+J to bring up the Downloads tab on the occasions you want to open something up. Some people will love it, some people will hate it, but it's nice to have the option.
Always Clear Downloads is a free download, works wherever Google Chrome does.