I've run into this a few times and used all of the above few of the mentioned ways of getting it off plus a few. A 12 point socket hammered on generally works, you'll want to use a breaker bar on it and not an impact though as the impact will probably make it loose its gip. Air hammer and really sharp chiesel point or reverse threaded sockets also work. If that thing is really stuck (I've only had to do this once before), you remove all the other nuts (hopefully you only have 1 that won't come off) heat the stuck one up red hot (pretty much liquid) with the torch and give it a pull / or a quick kick off center. This will destroy the threads on the hub bolt and the nut, but hub bolts are cheap and easy to re-install.