Inquisition warcries are the best.
My only gripe with Ultramarines is that everyone wants to make them, or Blood Angels.
I only like Blood Angels because I like seeing Eldar people getting set on fire by a Juggernaut's Heavy Flamer.
I like Ultramarines because they killed many, many, many Necrons, Chaos Space Marines, Tau Warriors, and Tyranids during and after the Horus Heresy. And almost every single marine has atleast one Purity Seal or Imperial Laurel on their leg or shoulder.
Stormbolters, Chainswords, Krak and Frag Missile Launchers, my favorite.