[MENTION=6685538]Luka[/MENTION] Jackinthegreen has a good point. D&D is not like other games. Tanking doesn't work the same. The concept of a tank is different because the rules are so different. I'll restate this. Please read the Players Handbook from cover to cover so you at least have a basic understanding of the rules as it shows from the topic of AC and raising ability scores(one of the basic rules of the game and raising ability scores is discussed in character creation too) that you're not familiar with them and don't have a clear understanding of them. Then when you are done pick up the Dungeon Masters Guide and read that cover to cover. Write down questions as you go if you don't understand something. If that doesn't answer your questions post them here and we will be glad to answer them. Then see if you can get a copy (buy, borrow, ect) a copy of the Rules Compendium and see if that doesn't answer your questions. I also recommend reading this from cover to cover too. This is very much a rules based game when it comes to combat and character creation so the more you know about them the better.
With your limited understanding of how basic game mechanics works its going to be extremely difficult for us to actually help you build a character since the terms we use and understand, you don't yet. You will but you need to do a lot of reading and gain knowledge of how the game works so when we use terms like AC, Saves, Fort, Ref, Will, Touch AC, Save DC, Spell Resistance, Damage Reduction, miss chance, cover, BAB, Attack Bonus, Enchantment Bonus, Enhancement Bonus, and a hundred other terms you at least have a good idea what we are talking about.
I've been playing 3.0 and 3.5 since they came out(about 10 years) and am still amazed at how much I learn everytime I build a character and visit the bulletin boards on here. I'm sure people like Dandu, kitcik, and emoplato have been playing longer as they make my knowledge base seem small.
Also I would bet you did a little internet research on "tank builds" for D&D and found this one and are trying to copy it. That's fine but making a photocopy of the toon won't give you the knowledge and wisdom on how to play the character or why it was set up the way it was. Different builds are set up for different campaigns and worlds. Its not a MMORPG where its all the same and you can copy a build and it works. In D&D there are a lot of things that have synergy and stack. Knowing why they work and how they work is essential to making a good build. If you don't know the why, lots of times you will miss out on how to play the toon properly as there is no guideline for this.
AC isn't a damage nullifier. It does nothing to the amount of damage that is done. It works exactly like emoplato described it. Perhaps another way to put is miss chance vs hit chance. Your AC is a number that a monster is trying to reach with his attack modifier+ a d20 roll. If the combined total of his attack modifier and a d20 is equal to or greater than your AC the monster hits you. If it is less than your AC the monster misses. This is a very simplified version of how AC works in general and doesn't cover all the bonuses, penalties and other things that go into it. It doesn't nullify damage though. (again, please read the players handbook and if you have questions about something feel free to post them).
As for stats I wouldn't recommend an 18 in Cha if all it does is increase your saves. That's nice but depending on what system your using to allocate stats that 18 may be of better use in STR as melee is going to be very important for your toon.
I'd also recommend that while it is a forum post, just about all the advice that's given is to help (in this case you). So when people like Jackinthegreen say the systems aren't the same he's trying to help you (and he's right). He's not saying you can't play a tank type toon, just don't come into a game you know almost nothing about, that works on completely different rules and systems and expect your prior knowledge of rules and their systems to be of value. They won't be (trust me nothing from WoW helps me in D&D or vice versa). Some tactical knowledge will transfer but not alot else will.
You really need to read the PHB and DMG. This will explain a lot of basic questions on how D&D works and basic questions that you have. Gotta walk before you can run right?
