If you want a fish thats full FW, with tons of personality, my first suggestion is the Abei puffer. I loved mine, was like a little aquatic dog. Begged for attention, went crazy when he saw his food cup, and even somehow made some sort of chirping noise if my desk chair wasnt facing him. Hed make the noise, id spin around to look and he would be quiet and dance around. As soon as I spun back he started doing it again. Sadly, I went on a cruise, and came back to a sick and dying fish. Thinkin my roomy, who I was on the outs with, had something to do with it.
Second recomendation is the Salivator. They are only about 2 inches, but try and get a male, they are packed with color and crazy attitudes. I have one of those currently and he is awesome as well. Smaller fish, but equally as fun to keep.
PS, count groups, or tank mates, out of the question for starters.