The Best Splinter Cell???? I don't know
The gameplay hasn't change a lot from the previous games expect some new things like the underwater swimming and killing enemies through the ice.
The graphics are great as they are in all the SC games,also Sam Fisher looks older than in Chaos Theory but as extreme as in the previous games.
I can say a lot of things about the sound because you must be quit during the game!!!LOL
So if you have played the previous games of the serie don't lose Double Agent and if you are an amateur in Splinter Cell, RUN to the nearest shop and buy it NOW!!! And remember to hide in the SHADOWS!!!:)