The only lens I have at the moment is the 17-55. Right now I'm up in the air on whether I should pick up a UWA such as the Tokina 11-16 or a 580ex II strobe. We all know that the Tokina is hard to find these days and having a flash is also useful. So what you guys think would be handy at the moment. Should I pick up the lens or the flash? Thanks in advance