MrSmish said:
"UWULR HUWURR UWAARRRLARLRRLWAAA!"
Actual battle cry. Guess and you'll get a hug.
"Wort wort wort!"
Brick from Borderlands? I love that game.
I have a few I use that are situational dependent.
If using a melee type weapon: "WWWWWAAAAAAAAAAAAAAAAAAAAAAAAAAGGGHHHHHHHHHHH"
If using a belt-fed weapon: High pitched, maniacal laughter.
If using a precision rifle: Slow, quiet exhale of breath followed by a gunshot.
If angry to the point of insanity: "HULK! SMAAAAAAAAAAAAAAAASH!!!!!!!"
In any other instance I use my fall-back: "SPACE MARINES! ATTAAAAAACK!!!"