I'd probably become a master thief. But the guy that gives the shit back and just does it for the kicks, like Magic Kaito.
Get a team of useful bros and steal diamonds and shit.
Yanmega for quick jetpack escape.
Porygon Z for hacking.
Sneasel for agile movements and window cutting.
Starmie for underwater escape and useful psychic powers.
Ariados for grappling hook action, and sticky situations.
Magneton for electric stuff.