It's the maximum amount of time by doing everything that's possible to be done in those games, at the first try. I'm a perfectionist when it comes to games that I like, I don't go to the very end if I don't have a 100% of the game xD

FF X is one of those examples, I didn't stop until I had 255 stats, 64000 max HP, 1200 max MP, all Dark aeons, Penance and Nemesis defeated, more than 120 blitzball matches won, will all my players at level 99, all the shots learned, all overdrives learned too, all the Celestial weapons powered up, so that accounted for 250+ hours of gaming, since the main history, until after the Jecht Final Aeon battle was only 60 hours or so.

Edit - Oblivion could be easily done with in less than 40 hours actually, but I didn't get to the main quest until I had all dungeons, caves and ruins explored, and all other side-quests done, all guild quests done, and even then, during the main quest, I went and closed the most number of Oblivion gates as possible

Tch... you sure are something. I thought I was hardcore in doing 200 hours.. or 150... forgot :P

Tales of Symphonia - 94 hours (something around that)

Final Fantasy VIII - 84 hours

Persona 3 FES: By the time I'm done with both chapters, I should be at 250... or more.

@Xen

At first I was only planning to do 200 hours as well, but then I got to the final dark aeons - Bahamut, Anima, Yojimbo and Magus Sisters, and got my ass handed down to me because I didn't had the stats to battle them xD I was averaging 130 stats for my main characters, so I spent a lot of time farming +4 stat spheres on the monster arena, especially those damn elusive Luck sphere.

Damn, I lost my Memory card with my FFVIII save, I think i was averaging 90 hours, I spent way too much time on Triple Triad xD

no Nintendo games (these are all my times, not included restarts that don't get included in the save files). I'm sure you can finish most of these faster than what I do, I consider my times average since I like to explore a little, but usually don't find every detail or take forever.

Fire Emblem: Path of Radiance (GC) - 35 hours
Fire Emblem: Radiant Dawn (Wii) - 40 hours
Metroid Prime 3: Corruption (Wii) - 20 hours
Okami (Wii) - over 40 hours (never finished)
The Legend of Zelda: Twilight Princess (Wii) - 40 hours
Professor Layton and the Curious Village (DS) - 10 hours
The Legend of Zelda: Phantom Hourglass (DS) - 10 hours
Lunar Knights (DS) - 10 hours, longer if you do all the extra stuff
Tales of Symphonia (GC) - 80 hours my first time, down to 60 hours afterwards

The other games I have I can't easily remember how long they took me, but I could look them up later.

Resident Evil 4 - 20 Hours
Zelda: Twilight Princess - 45 Hours (main story and a bit of exploring, not 100%)

I'll come back with more later

Majora's Mask: 16 hours
Wind Waker: 23 hours
Twilight Princess: 75 hours (I must've fucked around big time in that game :P)
Metal Gear Solid 4: 17 hours
Super Mario Galaxy: 32 hours (242 stars)
Mass Effect: 20 hours
Gran Turismo 4: 500 hours

Metroid prime 2: 35 hours( Lol, first prime game, I sucked XD)
Metroid prime: 18 hours
Metroid prime 3: 7 hours(I did it fast, but replayed it and did it like normal and that took 15 hours)
Zelda: The twilight princess: 40 hours and counting, probably 20 hours before I finish the game, so just take 60 hours. My very first zelda I played seriously.
Super mario galaxy: 40 hours, I collected all stars, so that means Luigi as well.
Super smash brawl: well not just singleplayer, but I've played it for 70 hours.

I remember some

Final Fantasy X : 205h
Final Fantasy VIII: 340h
Resident Evil 1: 3h (could do it in less than an hour)
Resident Evil 2: 5-6 h
Resident Evil 3: 6 h
Resident Evil 4: 11h
Oblivion: 140h
Fallout3: 134h
Uncharted: 16h
PES series: Infinity

Fallout 3: Main quest can be beaten in 1.25 hrs or 75 mins (http://blogs.ign.com/Bethesda_Softworks/2008/09/15/101489/)

I never rush through a game, at least on the first go. I enjoy the money i pay