The class that stands out most for me is the Rogue. Alternately known as the Scoundrel, the Thief, the Brigand, or any number of other names, if a game features a shifty character of questionable morals and a penchant for acquiring the things he wants through nontraditional means, then I usually gravitate that way.
Thinking of five of my favorite rpg characters I have personally played, despite not all technically being classed as rogues in the thieving burglar sense,
were played heavily skewed toward the stereotypes and tropes of the category, anyway.
I will play most any type of roguish character, from a sneaky cutpurse to a stone-hearted assassin, but tend to gravitate to the dilettante style...a rakish rogue who charms and bargains his way toward his goals. I think, perhaps, this is because I was extremely shy when I was a kid, up until around 11 years old, I guess. Maybe I'm just making up for lost time by portraying characters who are outgoing, as well.