blasphemy !

 Tekken is the greatest fighter in history !  (Imo..)

Overrated games..

 Halo ! (i've only played the first one, but i thought it was pretty boring and dull)

 HL2 episodes.. more of the same....

cnc generals .. Not a cnc game.

 mario .. Just mario..

Cod4.. Yes it's a great game... but it isn't the greatest invention since fire. 

Underrated !

Uncharted (YEs it is really that good.)

Universe at war: Earth assault (EPIC game. The best use of 3 different sides ever. Even surpasses starcraft)

Tekken (Greatest series ever, yet hardly ever mentioned among the killer apps) 

FFX (Easily the greatest rpg i've played) 

 Just doing this generation.

GTAIV - great game but way to much overrated.

SMG - again, great game but was too linear for me.

GoW - good game but gets old and repetitive.

I agree that Ocarina is a little bit overrated, but not in the same dimension of more modern games, such as the Halo Series.
The main problem about Ocarina is that it conditioned later Zelda games, such as Majoras and WindWaker that IMO are way better, but did not receive so much praise.

GTA4: Great but just way overrated
OoT: I loved it don't get me wrong but it's basically being called a god.
God of war series: Just never clicked for me for some odd reason....
Halo 2,3: It's been said already many time..
SMG: Great but not were its said to be.
FF Series excluding the 12th : Just found it boring no clue why...

Half Life 2...i bought it because i heard it was great...i played through a good chunk of the game and it was one of the biggest wastes of $50

I'd say GTA4 now. Not a bad game, but not a 10/10 across the board. Also, FF7. Didn't see the appeal in it.