Put in about 60 hours into FFIX. Had everything, gold chocobo, all posting done, all the Stelazio coins, all the coffees, most the cards, most the summons, got to disc four and the memory card corrupted. Never bothered to do all that again, and just watched my brother clear the ending instead.
Probably put in about 100 hours into Pokémon Gold, and still didn't finish the Pokédex.
But then there are many games where I've just spent loads of time not really doing anything closer to finishing the game, and have just arsed around for the fun of it. Any game where there just a non-story/career/campaign based ability to play (such as GTA, Burnout, Tony Hawk's, etc) tends to get a lot of time based on my ability to just goof around rather than actively trying to finish.