Barbarians are amazing tanks, with objectively the best taunt available, a stun, armor rend, self-healing and a powerful cleave attack, you really can't go wrong where a Barbarian is concerned!

Attribute points should be spent in approximately a 5 Strength : 2 Agility ratio initially to build attack speed. Once you have ~200 base Agility you can devote all your remaining attribute points into Strength exclusively. 

For your familiar skills, you want to invest in the 5% Increased Health from Vigorous and of 75 Strength/Agility from Gift of Dexterity / Endurance, ensuring you don't exceed 400 total Agility / Attack Speed.

At max level, the core setup is                            , combined with your choice of Olympian Relic;

1.      Towering Shield of Athena - Objectively best, incredible damage mitigation with a little bit of extra damage from the Strength, AoE armor buff, and a on-use effect to fully heal and replenish the mana of yourself, and all nearby players. Extremely useful for when the healer is OOM!

2.       Ares' Bloodthirsty Spear - Good damage and can further supplement damage using Ares' Sword of Command on your familiar. Used right, the regeneration from this item can provide personal survivability similar to that of Towering Shield of Athena while producing significantly more damage. However, you loose the group buffs and on-use group heal. That said, this is an excellent option if you prefer a Damage or off-Tank role!

3.       Thundering Hammer of Zeus - If no-one else in the group has a Hammer of Zeus, this will outperform Ares' spear if not combining the effects of Ares' Sword of Command on your familiar. Further, not only is your damage higher, but you also give a group damage buff and reduce your targets armor to increase over-all damage done. If however someone else in your group is using Hammer of Zeus as Clerics commonly do, you will have significantly better output using Ares' Bloodthirsty Spear as the damage aura does not stack.

>>Blanket Disclaimer: You, and every other player will need items from all crafting professions so there is no 'best' profession for any given class. If you are selfishly looking for personal enhancements, Alchemy is the only profession whereby you can't bring items you crafted through to another game, so this might be the best choice on a personal level, but increases dependency on others for crafting<<