Best Action Game Series (All Platforms)

I'm just curious what all of you think. I know there are some great series out there such as God of War, Ninja Gaiden, Devil May Cry, etc. If all of you could post your favorite and why, that'd be great.

Mine would have to be Ninja Gaiden and I've played quite a bit of action games. The engrossing story, extreme disembodying (thank you NG 2), and a challenging game that I could never completely just blow through. Overall I am a huge fan of Ninja Gaiden and woner your opinions on the matter.

GTA III and up are the most awesome games I have ever played.

well its not really action as those games have adventure in them so its action/adventure. but god of war is the best has the best combat and graphics, i like devil may cry but you get the same experience everytime, not bad though good atmosphere and combat with the coolest character.. then comes prince of persia, it has the best storyline it has the best platforming and game mechanics.

Action game though, i would say GTA. nothing is more fun and mindblowing.