How to transfer my apps, home, and OS X setup from an external Lion disk to an internal Mountain Lion SSD I installed an SSD (Samsung 830) as the internal drive of a Mid 2009 MacBook Pro, then attempted several times to clone the (now external) bootable OS X Lion drive using either SuperDuper or Carbon Copy Cloner to this new SSD. All attempts failed with disk writes failures (I tried two different SSDs with the same result: write failures). So installed Lion onto the new SSD using the OS X DVD installer and all went fine; then upgraded from Lion to Mountain Lion from the App Store. Again, all went great.

Which folders should I copy from the external Lion disk to the internal Mountain Lion SSD to get back all my apps, the MySQL server, PostgreSQL, ImageMagick, XCode installation, etc.? I would like to make the new Mountain Lion SSD contain all my useful apps so that I don’t have to reinstall from scratch.
The easiest way is to use Migration Assistant, which you can find in /Applications/Utilities/.

It can copy your apps, data and settings from your old disk if it's connected via USB, Firewire or Thunderbolt. You should end up with a mirror image of your old set up.

Start Migration Assistant, select From another Mac, PC, Time Machine backup, or other disk on the first screen, and From a Time Machine backup or other disk on the second screen, then follow the prompts.

If you need more detailed instructions, consult Apple's Migration Assistant Guide (you want the Time Machine or other disk migration section).