Personally I do enjoy longer games now that I am older, but it can hinder you as an adult. I recently rented LoZ: TP 2 weeks ago to be caught up in the zelda universe, and it took me the entire 7 day rental period, plus 1 extra hour, that I had to re-rent it for. And I think when I was younger I re-rented games all the time if I didn't beat it. I grew up on SNES and Sega Genesis. I actually didn't get into Final Fantasy until I was older, I liked Zelda more, which is probably why I love Zelda more than FF games.
I remember playing Vector Man over and over for hours then popping in Sonic and Knuckles, then playing Legend of Zelda: A Link To The Past, etc etc. For hours on end.
I played all the Half Life games, and was quite impressed, though I still feel a bit, empty after the last episode, it doesn't feel finished.
As well, I'm one of the few people, who can beat Oblivion in about less than 5 days, everything in it. I think my ending time was around 35-40 hours, and I did every quest, side quest, best gear, millions of gold, etc. I just knew lots of different ways to get around, and never spent a second wasting time. I think I reached the 50 hour mark after beating the expansion pack to Oblivion.
I recently beat Metroid Prime 3: Corruption within 3 days of 7 hours or less each night, and I worked 8 hours in the day time. I was disappointed it was so short, but please to finally reach the end of the great series... even then I beat the game with 98%.
So am I getting tired of long games, nah, I appreciate them, and feel more satisfied with them. Because I beat LoZ: TP and MP3:C at basically the best you can, I won't buy them, no point, I don't think I would replay them after spending so many hours getting the upgrades and extra stuff. Just a waste of time to me.
Tomorrow, I am getting Legend of Zelda: Phantom Hourglass, hopefully it will be as long if not longer than Wind Waker was, that was such a good game to me, I enjoyed it, different twist on the zelda series.