modern day, i would say tranmere are our most immediate rivals, but its mainly due to us not having a decent one, people clutch at straws.
obviously the two big ones are city and utd (purely on a local fan basis, their club as a whole, and the wider fan base couldnt give a :censored:)
after that id say hudds,blackpool and tranmere on an equal basis
and after that all your stockports/burys/dale etc
for me latics dont have an out and out clear rivalry, never had done. historically we have fluctuated through the leagues to much and all our local rivals have bigger derbies of their own (bury/dale, utd/city etc) to really give a damn about us