Metal Gear Solid 3. Incredible boss fight after incredible boss fight with a very tense and exciting story--and then Volgin tortures Snake so hard he pisses himself. Immediately following that was somewhere around three of the most perfect hours of video gaming that I have ever experienced which elevated the whole game to another level.
After the end credits rolled, all I could do was sit there in awe for a moment. Then I turned off the PS3, confident that I would never experience such gaming bliss (have I ever used the word "bliss" before? Hmmm......) ever again.
^^The best trailer the world has ever seen.