I don't see why it matters :P. The armor is there for you to pick what you like the most, so who cares about someone else's opinion?
You should probably tell people which campaigns you have too :P. It might also be more worthwhile to just save the gold for GWEN, if you're planning on buying it.
Out of what I've seen the most:
Prophecies
Elite Charr Hide and
Elite Platemail were pretty popular in the past, but I think that it was mainly for the bonuses. Insignias may have changed that.
Factions
I usually see
Elite Luxon and
Elite Kurzick the most. The male 15K Canthan is pretty nice looking, though less popular

. I wouldn't get if for my female Warrior, though.
Nightfall
Primeval is by far the most popular. I've only seen Elite Sunspear and Ancient once; I've never actually seen any warriors in Vabbian armor before.