I think all of the people who say Notepad++ is the best PHP editor haven't had a lengthy play with a proper IDE like Netbeans... I used to use Notepad++ and think the same thing... when it come to using xDebug and doing other stuff I really couldn't go back from Netbeans As long as you have a chunky enough machine I don't think anything beats it really. Nice and clean UI as well.
I love the Ctrl + Alt + O for opening files... beats Ctrl + O then looking for your file and double clicking it
I also love the Right click > Go to Declaration on functions