I have zero arena experience, so can't comment on that.
But for BGs I found out the only way to be useful is to put on a few (or more if you have it) pieces of plate healing gear. Don't expect to full heal a warrior (even with a crit) but spamming FoL and Cleanse pulls alot of attention...
...which is where the prot build comes in handy. You can last a long time & they normally don't pick-up on that before the DPS you were just healing start taking them down quickly. Ardent Defender + Imp Righteous Fury ftw. How I love those times when I last well over a minute while 3-5 opposing players beat on me. That's BG "CC" to me. kama-kazy, but what else can a prot pally do in PVP?
Other times it's handy to sit in the back healing the ranged & other "true" healers, but you'll still need healing gear to pull that off or you're OOM very quickly.
So to answer the question: if you're spec'ing prot, spec 100% for PVE and don't talk big in PVP.
PVE:
wowhead;0/46/10 put the last 5 where you want them.
Precision helps reduce parry's from bosses (which decreases incoming damage) and increases out-going damage/threat.
PoJ helps with our worst enemy - spells. Plus can be fun for those times your group is poking fun at you & you decide to take Crusader Aura off. Plus helps keeping you from getting stuck when on auto-follow :P
Imp Judgement can increase DPS and threat (at the cost of mana), but it's more useful function is to reduce the times judgements not up when you want to Judge/threat spike a MOB (i.e. just went for squishy w/ taunt down, came out of CC, 2 MOBs left and Conc. seems to expensive, ect...).
Kz
Edited, Jan 24th 2008 10:50pm by Killzon