As people have already said, Coheed & Cambria man. Check out "The Crowing", "The Velorium Camper I, II & III", "Elf Tower, NM", "Junesong Provision" and "Delirium Trigger".
The Used and FFAF are worth checking out too
Ummm....From Autumn To Ashes and Thursday too, although the former might not be classed as screamo/emo.
Eighteen Visions, but again, they might be classed differently.
My Chemical Romance are worth checking out too. Try "Helena", "Thank You For The Venom", "You Know What They Do To Guys Like Us In Prison" and "It's Not A Fashion Statement, It's A Fucking Deathwish"