Which game should I get first?

As of now, I'm trying to decide on the below games:

Prototype

Ninja Gaiden Sigma 2

Grand Theft Auto 4

I'm planning on waiting for metal gear solid 5 since I heard that there is swordplay instead of guns in it. As for assassin's creed, I already have assassin's creed 2, and I'll definitely get brotherhood :P

To make it short and simple, I basically like the rogue class in mmorpg, but I don't really like mmorpg's or rpg's so I want to find a game with similar playstyle or gameplay as a rogue, which is described below. I'm basically looking for games with thieves, assassins, ninjas, stealth. And you can read the below for more detail :D

In detail, I like stealth, daggers, assassination, stealing, running, versatility and speed (don't care much about swords , I'm actually more into the "rogues" and "thieves" kind of fighting and gameplay)
I like stealth games, assassin games, thief games, and ninja games.

So basically games like assassins' creed 2, ninja gaiden, or Thief series.

thank you

btw, isn't there stealth in every game? I mean, uncharted 2 isn't a stealth game at all, but you can still stealth kill in it.
So what defines a game as part of the stealth genre?

and I don't have a ps2

Also, I like the "rogue" in mmorpg's, or they are also called "thief" or "assassin" depending on the mmorpg. So which game do you think is similar to "rogue" or "thief" kind of gameplay? Like the stealthy, and hitting really fast, kind of attacks. Also, are there stealth games, where you can take down a group of people instead of one by one? Because, usually you wait for a group to disperse and then kill them, right? Can you like stun the group then take the group down?

And finally, I'm not just looking for stealth games. Are there other games that are like ninja-type games? thanks

And just one last thing, I don't mind games with partial stealth like assassin's creed.

So what game do you think I should get first?

thanks :D