Of the guys that have been out there long enough to have done something by now, Richie Wolfe and it's not even close.
When you start adding some of the guys that have just come onto the national scene in the last 5-8 years, you can add Jeff Carter, Joe Ciccone and some others. I bowled a pro-am with Ciccone and Randy Weiss and both of them are butter-smooth but no titles.
Wolfe's career window may be closing, though, so whereas Ciccone, Carter and others still have a chance to win, Wolfe might not.
Jess