of the three you listed...i'd say gwynn. kruk certainly had a "body by budweiser" but, he was on a team full of juicers so, you never know. and david wells, that guy is the perfect combination of arrogance and stupidity that makes anything possible.
tony gwynn seems like an honest, classy guy. plus, he was fat when he was a rookie and got fatter as he got older...just like the rest of normal americans. plus, his head didn't grow 3 hat sizes even though his pants did.