Sony MDR-7506
I hated these because of the treble bump, but I’m particularly sensitive to that. I went (gosh, almost 20 years ago?) to a set of Beyerdynamic DT250-250s and never looked back. Earpads and headbands are replaceable, too, though they cost a bit more overall than the 7506. I’ve also really liked the AKG k371 (but no velour earpads), and of course the DT770-80s.
I’d like to try a set of ATH-M50s at some point, but just haven’t had the chance.
Usually, when a maker has two models at a similar size and pricepoint, you get better driver matching in the “nicer” pair (e.g. k371 vs k361, ATH-M50 vs M40) or the nicer pair has better bass response; rtings.com does a decent job trying to measure them in various use cases.