Boros Aggro deck:
Creatures: Akroan Crusader - easy to target and get a quick 1/1 token. Also nice to get some cards down before Phalanx Leader starts putting 1/1 counters out on your creatures. Can stack Coordinated Assault and Martial Glory on the Akroan Crusader and Phalanx Leader to get a 2/2 hasted token off one instant.
Soldier of the Pantheon/Favored Hoplite - Both solid 1 drops and can be switched out depending on the opponents deck. The lifegain and blocking power of SOTP is nice against some early multicolored cards. Favored Hoplite is a free swinger/blocker on turns when he is targeted.
Young Pyromancer - With so many instants and sorcery cards in the deck there is no reason you shouldn't be spitting out elemental tokens like crazy. Also has ability to grow with Phalanx Leader's ability.
Phalanx Leader - Wonderful card that can turn your army of little tokens into a scary force. Aside from the WW cost to get out he is great to target with any of the non creature cards and with Martial Glory he can be targeted twice which gives every creature your control 2 +1/1 counters for RW mana.
Fabled Hero - Once he gets going is hard to stop, especially if you can swing through with a Gods Willing or get him hooked up with a Dragon Mantle, or both.
Boros Reckoner - Enough Said
Fiendslayer Paladin - To be brought in against red and black removal decks.
Imposing Sovereign - Brought in to screw up decks equally or more aggro than this one.
The support: Boros Charm - 3 uses that are all great, 4 points to your opponents face, save from a Anger of the Gods, or give an unblocked creature double strike and buff him a few times before the damage hits.
Coordinated Assault[[ - 1 mana to get 2 heroic Triggers. Seems ok to me!
[[Dragon Mantle - 1 mana to draw a card and give a creature fire breathing. Also targets for a heroic trigger
Gods Willing - stop removal, target creature and scry 1 for 1 mana.
Magma Jet - Puts 2 damage somewhere and lets you scry 2 which is huge for this deck to make sure you are keeping threats out on the board.
Martial Glory - A great way to target 2 heroic triggers on 2 or even the same creature. Works great with Phalanx Leader!