What players are risk-reward players

Phil Mickelson would be one of the more obvious answers

Yup, besides Phil, Cabrera came to mind immediatly, he is sick with his iron shots, likes to stick it tight no matter where he hitting from. Bubba Watson is another one that doesn't seem to ever lay up.

The PGA Tour keeps stats called "Going for the Green," which I guess measures some aspects of aggressiveness (thanks, Lowest Score Wins !)

Last year, Keegan Bradley led in attempts with 156 over 88 rounds. He pulled it off 72% of the time.

This year, the guy with the most attempts is Charles Howell III with 139.

Anyway, scroll to the bottom of this link to see all the various "Going for it" stats they keep:

http://www.pgatour.com/stats/categories.RAPP_INQ.html

Obviously it doesn't encapsulate everything about who is aggressive at pins and who isn't, as well as who is driving it well enough to put themselves in a position to even go for it, but it does show you who is laying up and who isn't. Interesting to look at.

The only par 4 I've ever seen him hit less than driver was the 74th hole at the 2013 Masters (not exactly, but he rarely uses less than driver on par 4s). If there's an opening he sees, it's a green light - regardless of the significance of the shot. The 72d hole at the 2013 masters - his approach shot - was pure risk-reward. If he hits that 6' shorter, it rolls off the front of the green.

Definitely Phil and Cabrera. Rory is another risk-taker. He plays very aggressively, which is why he fares really well on the softer setups, but hasn't fared as well on some of the faster and harder greens. He definitely is a flag hunter.