Don't you just love differences of (strong) opinion!
You're right, we are, at times, an opinionated group. That's what makes the forum exciting at times. I did say no question, Mike Sigel, and I still think that, given that the question did not specify the game. I took it to mean all the games, if you naturally exclude Snooker, and the various Carom games.
Mike won 14.1 titles from the late 70s to the early 90s, which many others do not have in their resumes. Earl and Efren do not have the 14.1 experience, but would certainly contend if the question was greatest nine ball or nine ball and one pocket.
Jim Rempe is mentioned, and a good point, another great all round player. Most of my viewing experience was Sigel coming out on top between the two, including a run of 150 and out in Chicago in 1989. By the way, Mike also ran 150 and out in 1992 against Mike Zuglan in New York, and I believe has other 150s, but can't remember exactly when.
Mosconi is mentioned, and rightfully so. Not to take away from that great player's record, but he was strictly 14.1. Names like Harold Worst do come up, but it would be hard to track down all the knowledge, as he passed away relatively young.
If the question had been a combination of tournament and gambling, I might include the late great Luther Lassiter as a contender, and others can come to mind.
Great debate, but I'll still go with Mike Sigel. I can't think of anyone that other players looked forward to playing less.
All the best,
WW