You need to narrow it down it a little.
Are you referring to First Person Shooter? (Or Third Person Shooter?)
Are you referring to RPG or MMORPG?
Are you referring to RTS?
Each game category has a completely different combat system.
For FPS, I like Battlefield 2 (sorry I skipped 3 and 4 so far) type of combat system. I liked Counter-Strike type of system too except for all the hopping lol.
For RPG or MMORPG, I like D&D based system from Neverwinter Nights. It gives so much personal customization when it comes to character development. And I think that battle system is cool for "automation".
If I want a game actually reflect individual player's skill/reaction etc., then I'd rather have something similar to Street Fighter type of combat system lol. Would be nice to have such system in a MMORPG.
Assassin's creed. Their fighting style and smoothness is so cool, and the cool free run rooftop jumps where you land on someone. Their fighting style is the best, especially because you as a single person can take on an army of soldiers and win.