1) 1989-90 UNLV: Yes, I'm aware they were getting NBA salaries, but man they were fun to watch. Larry Johnson, Stacey Augmon, Greg Anthony, Anderson Hunt, and George Ackles throttled just about every opponent in their path.
2) 1985-86 St John's- Chris Mullin, Mark Jackson, and Bill Wennington anchored probably the greatest St John's team in history. 3 of their 4 losses that season came to Georgetown (led by Patrick Ewing).
3) 2001-02 Alabama: I know it ended with a 2nd round blowout to Kent State in the NCAAs, but the regular season was great. Looking back at that roster... man we should've done more with it. Roster
Honorable mention: 1994-95 UCLA, 1992-93 UNC, 1991-92 Duke