my longest times:
1) FF7 I don't know how long, but I beat the entire first disc in two sittings, I got up out of my seat once.
2) RE2, spent around 10 hrs straight when I first got it, beating the game as both characters (starting with leon, ending with claire)
3) Smackdown! Shut Your Mouth, don't ask why but I felt compelled to beat season mode in one 5 hr + sitting.