depends on what style.. some of my favorites;
odins anime style is quite nice
midnightrider and sane are pretty dope at smudging
always liked tzls style
people might hate me for saying this but when ease was at his peak he would sometimes pump out some cool signatures with his chaotic image spam style
but if you asked those guys to do eachothers styles, it would come out bad
so its all preference, there is no number one (except me ofcourse but im to cool to make signatures nomsayain)