Mark of the great hunt. [spoiler]If you know, you know...[/spoiler]

I apologize as I won't be following the format of your request. (At work, not enough time to find the pieces) However every piece of titan gear that refers to the Sunbreakers, hallowfire heart, ashen wake, phoenix wake, are really cool in relation to your titan. If you play a titan and follow the story from D1 into now, You'll find that the sunbreakers are probably the coolest faction of titans in Destiny. They ar the ones who unlock the solar class, defend the city, etc. but its your titan that picks up the torch that they left behind. not the coolest entries themselves, but really cool lore in relation to your actual chararcter.