All tanks, look here.

I would like all tanks (warrior-tanks) to look here and share your spec with me, so we can figure out what's the best spec.

As an example, I will show you mine:
http://www.wow-europe.com/en/info/basics/talents/warrior/talents.html?050000000000000000000003500000000000000000000055511033021103531351

http://eu.wowarmory.com/character-talents.xml?r=Talnivarr&n=Tinydwarf

We currently have 8 warriors in the guild (which I think is 2 to much), we should make clear who are the dps wars and who are the tanks. I think you should also assign a MT that gets priority on the gear he needs, cause we'll need a goodgeard tank for Maulgar, Gruul and in the future Magtheridon.

Okay, I will say my meaning on your talents.

Tinydwarf: you shouldn't have Improved Revenge as it has no effect on bosses. Tactical Mastery is something you don't need either, as you will more or less only stay in defensive stance during a raid.
Things you can spend your points on; Improved Shield Wall (nice to have on bosses), Improved Saunder Armor (not a must, but also it could be quite nice), and the last one is booming voice, so that your shouts (Commanding Shout while tanking) will reach out to almost every party members.
Xionfighter: Things you should NOT have if you raid:
Improved Revenge and Improved Shield Bash as these has no effect on bosses. You could spend 5 points in Critical Strike Chance, which will give you more threat, other than that, almost the same as I mentioned to Tinydwarf.

To reply to all of Torbukjell's comments on Improved revenge, i'd say it is a good talent to have. You're right that it doesn't stun bosses, but you spend most of your time in instances and raids tanking trash, which in most cases it does effect and therefor is a useful talent, giving you more time to prep for threat and shouts, and means you take less damage over-all.

Yes, that is true. But I thought if the warrior was tanking Gruul for instance, I'm sure he can find something more useful than Improved Revenge to spend 3 points on. However, for the ones that keep to Karazhan and dungeons/heroic-dungeons, Improved Revenge could be a nice thing to have on thrash mobs.
All in all, I'd say it depends weather or not the warrior is tanking the "big boys" or just tanking relatively easy bosses.