[jessor]

I purchased two apps within the first few weeks after my switch to a MBP:

1) Moom (move/zoom windows) - http://manytricks.com/moom/

2) TotalFinder (enhances the finder) - http://totalfinder.binaryage.com/

Some other must haves for me:

* MacVim

* Alfred

* Cyberduck

* Homebrew

* VLC