The other option I go for sometimes, is to land on the right side of the green, so I have a decent, if long putt. That does depend on how good you think your putting is, but I prefer a long putt over a tricky pitch from just over the back of the green. If I think I can land it though I will go for it.
If you do go straight at the flag and land short, the best thing you can hope for is that the ball rolls back to the fringe, or even off the green. That way you do at least have a chance of playing a very delicate shot over the lump.