A hero should be noble and chivalrous, as well as misunderstood and despised, as nobility and chivalry are often misunderstood and despised. However, villains are more fun to create than heroes (see Milton's Lucifer versus Milton's God).
As for the second question, my favorite signature figure is my currently missing Black Falcon, with black pants, red hips, and a nose-guard helmet. He wields a sword in his left hand (therefore seemingly sinister and untrusted by many) and does not carry a shield. (Yes, I know; I can recreate him using another Black Falcon, but both he and I would know...
) During my personal Golden Age of LEGO Castle, he was responsible for saving the day for virtually every single adventure. He even saved Robin Hood's life a couple of hundred of times. Plus, all the LEGO women (all four of them!) loved him. Sadly, he has gone to Valhalla (that is, somewhere in my parents' garage), to return in time for the final battle between good and evil (as in all epic mythological stories).
For now, my sigfig is the guy to the left--with my recently acquired ninja mask (the attached sheath-clip-thing rules!), an old black ghost head, black torso, black gloves, black pants, and a dark gray broadsword in his left hand. In all likelihood, this noble, chivalrous, misunderstood, and despised hero is actually the Black Falcon Hero from the previous Age...but that is probably for another post within another topic.