My favorite set is the one where you bench it and replace it with something that doesn't look like it was inspired by Deviant Art.
No, really, 160/170 offenses don't go as far as they used to unless it has Specs, in which case it gets outsped by almost everything in the tier anyway. Its special defense makes it more of an issue imo. Mewtwo (all forms), Arceus, Darkrai and a few other things have slightly lower offenses (except Mewtwo Y) and enough speed and other redeeming qualities that they can reasonably expect to do other things, too.