The last few days I've been trying to think of some games I've never tried, or beaten that people think are a big deal.
Honestly can't say there are any.
If people rave about something, usually I want to see what the fuss is about. That said if I were to list the games I've found to be overrated, we'd be here all day.
Becuase of this I'll focus on the MOST overrated of each genre.
Half-Life 2 (FPS) :: Extremely linear, story only available to bridge gameplay areas, far too much focus on the ZPG which I honestly played with for a few areas but for most of the on-foot game portions I used the SMG exclusively.
Oblivion (RPG) :: Too big, too complex, poor ai, etc.. it was a mediocre RPG that had nice graphics and a first person perspective. Niether of which made up for the fact it was an offline MMO style game.
WoW (MMORPG) :: If I wanted to do the same thing for hours, I'd play tetris. Atleast then I wouldn't have to deal with players as nakied cubes doing a little jig in-front of me.
Prince of Persia (Action Adventure) :: Original, Innovative, but seriously let down by a crap control and camera system. If it was playable it wouldn't be on my list.
Hold'em Poker (Card Game) :: Simply because they never have any other damn style of Poker in game form for some reason. Personally I've never really liked Hold'em and prefer 5-card stud.. then again you never see Gin Rummy or Go Fish as bloody computer games. WHY!?!
Roller Coaster Tycoon (Sim Game) :: Sorry, but it's just a theme park game with a single ride available. That's like playing through Doom with *only* the Shotgun.. sure it's the best weapon, but variety is what makes the damn games work.
Resident Evil (Horror) :: Can't say much except, Dino Crisis had a better storyline and puzzles that made sense to what you were doing in the game rather than some random cryptic puzzle someone has obviously had waaay to much time to plan in the bizzare event zombie mayhem did break out!
oh and here's a special mention for Final Fantasy. Yes, they're good and enjoyable.. but 90% of the time like in most RPGs there comes a time in each when you HAVE to spend several hours just leveling up to beat a specific boss. I hate doing the same thing over and over and over, just so I can continue a storyline. Due to this FF is specially mentioned as possible THE most overrated series of games EVER!!
Now no one get me wrong about the games I've mentioned above (except WoW) I do like each of them. It's just they're not AS good as the gaming world seems to want to believe.