While tanking I open up with shield slam, and use it anytime it is up, and in between I sunder and revenge until I have a stack of 5 sunders up and the switch between devestate, revenge and sheild slam, throwing in mitigation abilities (shield block, thunderclap, demoralizing shout) when appropriate. if I have excess rage I will toss in heroic strikes. I found that with my slow (2.2 speed) weapon, devestate generates more threat than heroic strike, but the general consensus is that with a fast weapon you want to ignore devestate except for sunder refreshes, and use heroic strike. As a tanking prot warrior sheild slam is the highest threat generation ability, and revenge is the most rage efficient threat generation, and devestate/heroic strike are great rage dumps. A stack of 5 sunders also increases the threat of your threat generation abilities due to the increased damage.
My experiments with taunt have shown me that it only is useful if somebody else already has agro - it doesn't make sure you keep agro if used preemptively. In trash encounters where they don't hit hard, I usually get rage starved, so I will let somebody grab agro and conserve my rage, then using taunt, shield slam, heroic strike to get agro on the mob and go from there. if the DPS is paying attention to threat, then I will just use revenge/sunder on trash.
For soloing, I like using a slow two-handed weapon and use a slam spam - the slower the weapon, the higher DPS increase you will see. If I'm worried about survivability, I will use strength gear, with sword and shield for solo DPSing (I use the sporregar rep shield, lots of strength on it, and sufficient armor). I find for grinding, that dual wield also works as long as the mobs are low enough level that I don't miss too often and just spam devestate, and build up rage on autoattack. Since devestate is an instant, and it doesn't reset the autoattack counter, this is an easy way to boost DPS. Heroic strike is ok, but it only applies to the next auto attack, and so you actually end up with both less rage, and less DPS than devestate spamming. Against casters, I always use sword and shield (spell reflect FTW!)
As for stats, I have been playing around with some math, and for pure survivability, I found out that 6 stam > 4 Def > 4 dodge > 4 parry > 4 agi > 4 block rating. Personally I view block rating as a agro stat since it helps with rage generation (getting hit), but it does help prevent crushing blows. I haven't played around with exact ratios, but it does depend somewhat on gearing. As for agro generation, agi > Shield block value > strength > hit. And of course a higher DPS weapon will generate more threat and rage. Gemming gear I tend to follow the socket colour, since it tends to balance out my stats that way, as opposed to what alot of tanks do and just stack +12 stam gems. I.E. a yellow socket gets a +4 def/ +6 stam, a red socket gets a +4 agi / +6 stam (leaning towards the +8 dodge gem though), and blue always gets a +12 stam. On DPS gear I tend to stack strength over anything else.
Anyways thats the way I play my warrior.