Speaking of Sublime Text (2), I find that it has a lot of the features that Light Table is supposed to have. I can work with an abstracted view of file heirarchy (need to find a file? Shift+Cmd+P and then type anything - the fuzzy search beats wildcards any day). Need to find a function? Cmd+P and then type what you need.

Maybe in some version of ST2, they will add the ability to see documentation in an overlay when you mouseover a method (or maybe someone will write a Python plugin to do that). This editor already seems to be a long way towards the goals of Light Table.