While installing IntelliJ Ultimate 14.0.2, I could not download any of the featured plugins. It appeared that they were being downloaded as the status bars completed but after, they came back with "Cannot download plugin".
After going into the Plugins screen, none of them were installed. In particular:
Attached is screen shot.
Don't know if this is a problem in that screen, but I was successful into going to the Plugins screen and installing each of them individually.
I did run into problems installing Scala, which came back three times saying it was not reachable. I did get it to install on the fourth attempt.
By default, have the PHP, Ruby, and Python plugins installed. Since you have products that already exist via PhpStorm, RubyMine, and PyCharm, users who are upgrading from those product lines to IntelliJ would be more convenienced to have them all installed instead of having to install them individually.