Madden - Madden is a great game but NCAA Football and Blitz: The League are better. The 2K games were better before they were run off the market. Arena Football will probably be at least as good as Madden. It is the only game for the NFL but it isn't the most fun or most realistic football game (with the exception of Madden 06). Madden 06 is much less overrated than other Maddens because the QB vision and Truck Stick change Madden from an college-style aerial shootout into a game of professional football.
Final Fantasy VII - This game was great 10 years ago because of its graphics. Now that the graphics don't hold up to current games, it is obvious that Final Fantasy X is the best Playstation Final Fantasy game. The gameplay for the 7th FF was very flawed and very few people actually like the story (but you wouldn't know it from the Final Fantasy forums).
Grand Theft Auto 3 & Vice City - These games were among the greatest ever when they were released but San Andreas fixed every glitch and gameplay flaw, eliminated load times and is a much bigger and more interesting game world. Saying that San Andreas is not much better than these 2 games is ridiculous.
WWE Smackdown HCTP - This game had the revolutionary gameplay improvements that are to be expected in every WWE Smackdown game. It was good when it came out but WWE Smackdown VS Raw had better gameplay and graphics. The only thing this game did better than its sequal was the Season mode. WWE Smackdown VS Raw's sequal is the most revolutionary game in the series and will completely outclass this game.
In general, an overrated game is a game that made a huge impact when it came out but was later improved upon to the point where following games, while not as revolutionary, were better. 1 major exception to this is EWR which isn't overrated because it remains the best free wrestling management game available, even though TEW might or might not be better.