So I'm interested in getting a new hero and I really like being able to stun/disable people as well as be useful in team fights. I played Alistar when he was free and had lots of fun headbutting people to danger zones. The champions that caught my eye are:

Amumu
Blitzcrank
Veigar

Any thoughts or suggestions?

Amumu is really good, and his ultimate can stun an entire team. I recommend him.

Well what are the pros and cons for the crowd controlling tanks? Blitzcrank seems fun to play, but the fact that he costs a lot makes me wary of getting him without test driving. Sion has done well in games that I have played. Also is Alistar good in high end play?

Both alistar and amumu are good higher tier tanks. Shen is also a good tank with cc.

The pros for amumu are that he has an amazing ult that can stun an entire team, has a skillshot that can stun, has good aoe damage, and has alot of health. Cons are that 1 of his abilities is a skillshot, his ult is greatly reduced by merc treads, and he requires good team communication to use properly.

The pros for alistar are that he can heal for sustained pushed, has 2 forms of cc in headbutt and pulverize, and his ulti makes him near invulnerable for superior tanking. The cons are that he has a slower base speed, slower attack speed, relies a little to much on the summoner spell flash, and has longer cooldowns on headbutt and pulverize.

The pros of shen are that he has an aoe taunt, he has a damage mitigation ability, his voral blade hurts alot and has a decent heal attached, he can farm rather easily, if he is focused, his passive makes him deal alot of damage fast, and his ulti is a teleport and a shield for himself and an ally. The cons are that with the recent nerf, he's not as gamebreaking, he only has 1 form of cc, his taunt is a skillshot, his feint ability isnt very good, and he has a lower base hp for a tank.

The pros of blitzcrank are that if you land the rocket powered grab its basically an instant kill, he has very good damage for a tank, he can push well, his passive gives him a mana shield, he has 2 forms of cc in rocketgrab and powerfist, he can chase or escape decently well, and his ulti is not only a passive damager, but an activatible aoe damage. The cons are that he can be focused down easily, his skillshot is moderately hard to land, his tanking ability in terms of eating damage is sub-par, and his escape mechanism also slows him after a few seconds.

Overall, these tanks are all pretty good. I would recommend either shen or amumu.

Alistar was considered the best tank in high level play before Shen came out, I suspect he is still an excellent choice unless they remove flash with no replacement (he needs flash like blue wizard needs food).

Although, I wouldn't worry overly much about high level play. Not trying to be mean and say you'll never get there (most don't, but that no reason not to try), but most if not all champions are perfectly fine in most levels of play IF the player is good and knows the champions strengths and weaknesses. By the time you get to the Elo where most of the tier ranks are based out of, you'll know which characters are the go to picks for competitive play.

Blitz is awesome initiator and not that hard to rocketgrab, especially from cover, but man, he is FRAGILE for a "tank". He has no healing/survivability stuff whatsoever, most of his combat duress comes from mana shield. His combats are mostly spent at deliciously low health, trying to survive the attention he brought onto himself. That's unpleasant, but at least your team loves it.

Thanks for your input =). Do any of you have knowledge on how these characters play 3v3?

I ended up getting Amumu and I like him a lot! He will surely tide me over till I can try the other champions in the coming free weeks.