Learning to use new tools

So these days we've got Ubuntu, Ruby on Rails, and Aptana.

I'm used to running Fedora, writing webapps with PHP, and doing my development in a text editor such as vim or emacs. It seems like there's something new coming out everyday, and it's a choice between checking out these new offerings or getting something done.

I figure that if the tools I'm using are good enough to get things done, why switch? I'd only consider using a new tool if it allows me to do something that I can't do with my current toolset.