Hey there! If you'd like to know what's been covered so far on this thread, please indulge in the preceding 7 pages of discussion on this topic.
Some counter thoughts which have been mentioned already:
-SN1987A, in which neutrinos were determined to be traveling slightly slower than light in vacuum.
-LHC, in which the speed of light in vacuum, as well as its functional role as the absolute speed limit of the universe through SR, has been verified to many orders of magnitude greater precision than the OPERA experiment.
You could be right, in fact I've got $5 I'm betting against $50 of Doogly's that the results will be verified within a year and we'll have to consider another reason why neutrinos are unthinkably weird. (I don't actually think I'm right in my bet though, I just like the 10 to 1 pay off). And at this point, other than experimental error, the most likely candidate is a worm hole inside the Earth. Just to give that some perspective.
As for the backwards in time thing, the worry isn't so much for practical concerns as ontological ones. You don't have to actually build a time machine, if you can just tell me that you have proof that it would be theoretically possible to build a time machine under certain circumstances, that'd be enough to radically re-frame the way in which we view the world. I mean, you can just go by Newton's laws and balk at GR corrections as totally unnecessary for day to day life, and you'd be right, but also very silly to ignore the ontological significance of the theory.
Technical Ben wrote:PS, doogly, way to miss the point.