Hands down, no doubt about it, the madden/ncaa football games. They are pretty much the same games so that's why they are listed together. I can't tell you how much time I have spent whipping some tail ( computer or human ) playing these ea football games.
The Elder Scrolls games are definitely #2 for me. Hundreds upon hundreds of hours spent playing these games. You can't go wrong with Bethesda.
Tecmo Super Bowl is #3. I find myself, to this day, with the updated rosters, playing and loving this simple arcadish take on the game of football.