Favorite Video game soundtracks.....123go!
 

My #1 would have to be Deadpool's theme.....https://www.youtube.com/watch?v=xelNyMZFL6s

The first one to come to mind would be the "Ezio's Family" track from Assassin's Creed II.
One of the best: https://www.youtube.com/watch?v=O0i6YFrSs6c

all of the witchers ost.Has a its own charm in it

First thing that pops to mind is the great soundtrack by David Bowie and Reeves Gabrels for a game called The Nomad Soul. That was probably the best one for me.
I also remember the NIN soundtrack for Quake and how Type O Negative provided an instrumental track for Descent 2 or something.
One really memorable soundtrack was in a little known but really great indie title Jenifer.
There have probably been some others as well, but that's what comes to mind.

Oh, oh! And almost forgot! But Yasunori Mitsuda on Radical Dreamers is just aural heaven!