They are going to be called in to righteously kick the shit out of deamons and heretics before fucking off back to Titan for tea and crumpets, leaving the chaos gods thinking "I fucking hate those guys"
first blood angels, but i would go for 2 assault cannons instead of all 4 las/plas. and drop a priest and get melta bombs on all sergants and 2 power weapons, for the 2 squads with the priests. hope this helps!!