I can't be the only one that A) Programs in multiple languages and B) Would gladly pay for language add-one to one IDE.

I'd be happy to use IntelliJ for everything!

I have IntelliJ Ultimate, but I'd actually love if my license would also be good for PyCharm, RubyMine, etc.

Obviously, you can get much of the same functionality by installing all the relevant plugins in IntelliJ. But, the per-language IDEs are nice in that they are tailored for that specific language. Also, they have a lighter footprint, since the plugins for the other languages are not loaded. And I don't see disabled JRebel buttons, etc. when working on, say, a Python project :).

The extra niceties of language specific IDEs over IntelliJ is supposed to provide a reason for giving JetBrains more money to keep up the good work. Their tools are surprisingly cheap when you pay for your own license.

Well, except for the Mac-only IDE (AppCode I think it's named), the other IDEs are just tweaked IntelliJs with stripped down configurations and language specific plugins.

Those plugins can be installed and used in IntelliJ itself, so you can have Java/Ruby/Python/PHP/Javascript/etc support, all in one.

AFAIK PyCharm comes with stuff (like Django support) that the Python plugin doesn't have.

I've seen references to Django in the Python plugin as well.

I am the lopposite? of you. I program in multiple languages and _like_ having multiple IDEs so that it doesn't turn into the cockpit of a 747. Once I switch contexts, I relax and stay for awhile.