Morkus from Orkus
I didn't love THAC0, but it also wasn't an annoyance as it literally took 2 seconds or less to figure out.Eh, some people swore by THAC0, other people swore at it. Tables were so very ur-Gygaxian, and I can't recall not seeing a game with the DM Screen.
I mean ... c'mon.... that Trampier two-piece panel. That artwork, perhaps more than anything (yes, even more than the DMG or PHB cover) instantly evokes D&D for a whole generation.