What if Bilbo (or Frodo) had TRIED to use the full power of the Ring?

[Sardy]

Silly as it may sound, I just picked up "The Hobbit" Playstation game to play with my son (whom I've been reading The Hobbit to, and he is loving!)... in the game (as in the book) Bilbo can use the ring to turn invisible and get out of some sticky situations. Playing this aspect of the game got me thinking...

Suppose Bilbo or Frodo had known the full history and power of the Ring... And suppose (let's for just a moment let them go "out of character") that they had decided to attempt to use the Ring to it's full power, or the full extant of their abilities, and to evil purpose...

Just how powerful might the Hobbits have become, assuming their willingness to turn to evil? With a bit of practice, what powers/abilities might the Ring-bearers have wielded?

To take the hypothetical even just a it further, how might the story have changed if the Fellowship (and the White Council) found themselves unexpectedly dealing a power-mad, Ring-wielding hobbit?