[center][b]Underrated:[/b][/center]

The Darkness. Go check it out. Online blows, but it's one of the most entertaining story-centric first person shooters I've ever experienced. 

Also, it provides one of the greatest video game lines of all time.

[youtube]https://www.youtube.com/watch?v=fM_Fc_rF6a4[/youtube]

[center][b]Overrated:[/b][/center]

Going with perspective here. Modern Warfare 2. It received a ten, everyone loved it, but man, the online play was a serious step down from the original imho. This was the beginning of the end, you could see the signs of cookie cutter fuckery before the series descended into bleh.