Hmm...
Baldur's Gate 2, but that's because around 8 years ago my classmate lended it to me, than asked it back a few days later, and I only bought it on GOG recently.
The original BG took me years, but that's because I didn't speak a word of English, and I had no idea what to do, and I was just walking around randomly :P I only finished it for the first time after I got my hands on a fan-made localisation.
Might and Magic 6 The Mandate of Heaven took me years for the exact same reason: zero English knowledge, I was just randomly walking around killing everything... again, I finished it years later, when a fan-made localisation was made :P
Also, chapter 2 in The Witcher took me six months... >_>
Forgot the most obvious: Monkey Island 2!! I only finished it this year for the first time, and I had it since.... idk, but I was still an emelentary school student. But again, it was because of language problems. I understood that I have to combine items, to get more items, but I was just trying randomly XP Never made it out of the 1st island, until recently :D
Post edited May 15, 2014 by MadyNora