It depends on your Attack Rating...Highlord's is probably better for PvM where you don't need extremely high Attack Rating...For PvP it depends who you're going to duel. Against casters highlord's is better but against high defence paladins/barbarians you're going to need the extra AR from Angelics to hit.
Depends how much AR you have with Ravens and with Angelic. Ofcourse Highlord/RAven is a better combo as raven gives dex which means less dex for block which will in return give you more life. Also the DS on the highlord helps.
If your AR is sufficient, then highlord/raven is better. Though if you need AR, then you'll need to use angelic.
You're going to want to wear whatever makes you most effective.
angelics = other pallys, most other melee classes, with stupid high def/high block/dodge... dealing little or no elemnetal damage.
ravens/HL = most other classes.
ravens/grid = good versus elemental melees aka. dreamdins/fireclaw druids/enchantresses etc.