I believe I did everything there was to do in the original US release of FFIV, as well as the actual version. I also believe that I did everything you could do in the GBA port. Didn't for the PSP port/remake or the DS/PC remake. On average playthroughs I usually don't bother with the random summon drops or try to get the Adamant armor because the process to gets those are time consuming and annoying.

Something more definitive: Did absolutely everything you could in FFVII and THEN some...except getting all the Enemy Skills because who cares?