No-brainer if the A77+18-135 is the same price as the camera on its own.
Depends if you need the wider angle, if so then sell the 18-135 on EBay - it won't be up there very long.
the 18-135 stays on my camera 90% of the time now as it's not too big and heavy and the results are generally nice. (Corner vignetting is my only minor gripe with it if the in-camera software fix is not turned on.)
Took these with it at the weekend: