Gay has the talent to go number 1, but probably won't due to his passion, or lack there of.
IMO the best place for Gay is Toronto. He won't have to be the number 1 option (Bosh, Villanueva, MoPete, and James if he resigns will all get shots before him), he won't have to defend the best wing player (Graham is developing into the defensive specialist), and he won't have to carry a team like most rookie wingmen (Calderon is a very good PG, and came just short of a couple triple doubles earlier this year).
Williams is harder to project where he will go. Some scouts love him, but not all (loved his ability to take over games in the clutch, but hated how much he turned it over in the tourney.) IMO the best place for him is Philly (another guard to penetrate and help AI,CWebb)
Boone will be a late 1st rounder, and will not fall pass the Nets.
to answer someone question, yes Brown and Anderson both should be drafted, but they will be 2nd round picks. Brown will be drafted before Anderson, but RA is too good of a shooter to not get drafted