I have had nice roosters from the following breeds: White orpington, Cochin, and Barred Rock, (so far- he's still young, but not aggressive at all so far.) The Wyandotte roos last year acted like they would be pretty nice, too- but I just couldn't keep them. My Jersey Giant was not too bad- might have been a good roo if I had kept him.
Trouble:
I have had trouble with EVERY New Hampshire cockerel that I've had, (the hens are sweet as can be.) My personal inclination is to stay away from the Rhode Island Reds as well because of my experience with the New Hampshires. Dark Brahma was pretty feisty, and so were the light Brahmas. Old English Game Bantam was a trouble maker, too! We had a Silver Polish that was fairly aggressive as well. Keep in mind that all of my experience is with hatchery stock- a private breeder may give different results. I do believe that you will have to judge each rooster on his own merit despite the breed, but some breeds will give you better chances than others.