Sometimes I will have a project that has a large amount of php files and I might accidentally close one (ctrl + w) or on purpose, whichever... Anyway, I was thinking it would be useful to have a short cut key to re-open the tab that was previously closed, sort of like how with firefox you can do ctrl + shift + T to reopen previous tabs.

i too think this is a good idea

Just closed file is always on the top position in the history list. Just click on the drop down right to the Open icon and either select the topmost file or press 1