While i'm tempted to rush in and defend 40K from the hate, I know that It can be stopped with a single fact: What you hate, we love, and you're 100% correct. We just get to have fun with it, you poor bastards.
My second point is to say that the Ultramarines are nothing but liquid sex and awesome. Look at that picture,
look at it. That's god damn Marneus Augustus Calgar, the living embodiment of kicking ass and recording your title on an honor roll of the slain. One day, he was out killing stuff, and realized it was really hard to punch tanks to death with his hands full of assault weaponry. So he decided to turn his fists into assault weaponry, so he could punch you while shooting you and perhaps even hold yet more assault weaponry with his now free hands.
Ultramarines: Popular for a reason. And have the word Ultra in their name. Which is awesome.
For The Emperor.
Note: Still, would have preffered space wolves or Black Templars, hell, i'd love to play as Alpha Legion (I always knew they were good guys)