LUX OK, it seems few on here consider Aldershot to have ever been our main rivals (and, as I said, my formative years were when we were playing them regularly, so I am biased). My point was, though, that Oxford and Swindon do not consider us to be their principal local rivals at all. Indeed, in the case of Swindon, we are probably behind the Bristol clubs, Gillingham and even Cheltenham as well as Oxford.
I suggested Aldershot because there is at least some form of mutual dislike. We are most certainly the team they consider to be their hated rivals. Ditto Bournemouth, but that is only one way.
It should be Brentford (closer than Swindon, ignored by their neighbours, played them loads of times over the decades), but that has never taken off. I quite like them, tbh.
One last point, in a recent survey, we were apparently voted Wolves' second biggest rivals (disliked club), after WBA. I think we have had lots of key and tasty meetings since the 80's.
I like the fact that your suggestion that the only one with real mutual rivalry was Aldershot then being followed by a string of people saying Reading fans don't give a toss about them quite funny.
I'd quite like to see that poll tbh.