I've been playing my Druid so much that more than two free bag slots is a luxury. PvP gear, melee DPS gear, tank gear, healing gear and ranged DPS gear. Gotta love it.
You only really need a tanking set at level 70ish when you enter Northrend, but even so, if you have 1,000 gold to blow on dual-spec, getting a Protection talent build for tanking makes everything a lot easier and you won't necessarily require a tanking set.
I've run The Nexus with a Fury tank and I've got to admit, it was hell. Not so much the damage, but he couldn't keep aggro on group pulls to save his life (or ours). Protection gives you a lot of AOE aggro and control abilities, like increased Thunder Clap damage and Shockwave.
Plus, and this is hear-say only since my own Warrior is level 51, I've heard you can level as Protection.
Edit: Northrend, not Outland Edited, Aug 13th 2009 10:20am by Mazra