I just switched from an old Mac mini to a new one (double the RAM and hard disk, faster graphics etc) and restored the user folder from my Time Machine hard disk backup. 98% of my entire working environment (files, folders, icon placement) got put back straight away on the new machine. I was stunned.
But there were a few "?" icons on the dock, where a few of my third party apps were missing (Handbrake, Seashore, Audio Hijack Pro, Cyberduck). So I installed them from the latest versions off the web. And you know what? ALL of their settings, preferences and plug-ins were just 'there', stored in my user folder. There was ZERO work to do on any of them.
Upgrading to a new computer used to be a nightmare for me, once every two years or so. This last Mac to Mac transition has been an utter revelation. Kudos to the OS X engineers.