Sat next to Jamaal Lewis on a plane
Played golf with Roy Williams (WR) and Ray Allen
Johnny Football (multiple times - the f**king man), Colt McCoy, Lache Seastrunk, Nick Foles, Ryan Swope, Aaron Williams and a bunch of Texas/Penn State players.
Teddy Ginn Jr.
Travis Fryman
Jim Thome
C.C. Sabathia
Travis Hafner
Adam Dunn
Brandon Phillips
Trent Dilfer
Drew Brees
Bruce Jenner (current, not in his prime)
Kemba Walker
Jim Calhoun (guess it sort of counts)
Almost every important 2012 US Olympian - from LeBron to McKayla Maroney to Ryan Lochte to Coach K and Missy Franklin, but not Phelps. A lot of them were awesome people, some sucked (your assumptions are probably accurate).
My conversation with LeBron is the greatest one I will ever have in my life. KD was probably the nicest of the bunch, but Kevin Love was great too. Didn't really converse with them all, but a lot of them were nice people. Helped that I had the position I did, because they may've been douche bags if this were in the public.
Possibly forgot a few.