Thank you for the Kasparov reference, pfren. I would imagine Kasparov would be highly represented on a list of best games, it would be wise if I want to improve to study his games.
Best game ever

What, nobody's mentioned Botvinnik-Capablanca AVRO, 1938?
Yes, I too prefer Kasparov-Topalov, but Botvinnik-Capablanca is still one of the 5-10 greatest games, even now. Take a look at Stein-Petrosian for a similar sac of the a-pawn for positional considerations. Here's the Botvinnik game, without annotations.

My first question was about a the most flawless, no blunder, not the most beatiful.Kasparovy- Topalov is the best, in my opinion, still

Reti vs Bogolyubov, New York 1924 is one of my favorites:
http://www.chessgames.com/perl/chessgame?gid=1030774
One of the games I like particularly was a battle between Walter Browne and Vasily Smyslov from the eighties. Smyslov reminds us that the king can also be a valuable piece in the middlegame and not only a victim of attack. He decides it's a good day for a stroll in the woods in a queenless encounter. I'm rather partial to this game for the sheer logic and clinging on to the metaphore of wood, sticking to one's principles. It must have been a guilty pleasure for Smyslov to score with one of his pet lines. Well, anyway here it is... enjoy!
I think that it was done but I can't find the information. If we put all the GM' games of history in a good engine, what is the game that the computer will " think was the best, the most flawless?