Where would Joomla! be without the custom themes and extensions for just about anything we can think of? Sometimes, when I am browsing I find an extension for something that I didn't know I needed until I found it. Obviously, we have
extensions.joomla.org/
but that repository does not have them all. I'm hoping to see it branch it some way to better differentiate the pre-1.5 extensions from the post-1.5 extensions.
There is only a couple of extensions that I ever use. Mostly because I am familiar with their compatibility and we all know what sort of disasters two non-compatible extensions can cause.