I wasn't aware that there was light dragon armor. Time to grind my smithing...

I made my Dragon plate as soon as I had the skill, and used that until I collected enough deadra hearts for Deadric armor.
Deadric has better AR but Dragon plate is easier to make as you can't step foot outside your door without a dragon harassing you.

Both perks are great; both armors can reach the cap.

If you wear deadric take the dragon smithing perk anyway; it can make you alot of money selling
Legendary Dragon Plate stuff.

Max damage reduction = 80% = 567 armor rating.

So basically, pretty much all armor smithed to the max+ some perks = the best armor...

http://www.uesp.net/wiki/Skyrim:Armour

Ick, High leveled armors look ridiculously out of place to me, Though, Dragon upgraded all the way will probably be the strongest....and ugliest....

Nope. I have both Dragon and Deadric smithed to Legendary.
Both hit the armor cap; but Deadric still has more AR.

Take the steed stone also, it goes good with daedric.

dragon plate is lighter, but slightly less protective than daedric. by the time you can smith them ebony will hit the armor cap though so it doesn't matter except for looks

I believe all armors can hit the cap when smithed to legendary and with the appropriate skill\perks for the type of armor.

So the "best" would be which ever you like the looks of...

Dragon I think, not sure though.