I have to make a few differentiations here. Best finish to a race would be Lezak's anchor leg of the 400 FR relay or Phelp's win in the 100 FL at the same Olympics. Best race start to finish? I will go with either the 400M FR from the 1976 Olympic Trials, or the 2017 Men's 1650 at NCAAs (more here: https://swimswam.com/clark-smith-smashes-american-record-win-ncaa-1650-free-1422-41/ ). All of those were obviously ones I witnessed live (minus the 1976 400) on TV.
However, best race I ever witnessed live in person on the deck would be the 100 BR final at the 2003 YMCA Short Course Nationals, between Michael Alexandrov and Matt Lowe. A sort of "before they were REALLY FAMOUS" race. I watched those guys go stroke for stroke and they were tied at the 25, 50, AND 75 of the race, and then Lowe clipped Alexandrov by .01 at the finish, effectively winning the event with the last stroke of the race. Runner up would go to Josh Schneider in the 50 FR at the 2013 Oklahoma Elite Pro-Am. He dropped an 18.98 in the final of the 50 FR shoot-out. First (and only) sub 19.00 FR I ever witnessed live, and so I don't forget it. He made it look easy.
I don't remember the 1976 400 M FR, but I do recall the 1500 as being quite a good race. I don't know if I saw it "live", ABC may have run it on tape delay, but it was effectively live for me because I didn't know the outcome. I also remember being stunned by the size of the biceps and shoulders on the GDR women. I'd been swimming for a few years by then, enough to have been to quite a few swim meets, and I'd never seen a female swimmer who looked anything like that.
I don't remember the 1976 400 M FR, but I do recall the 1500 as being quite a good race. I don't know if I saw it "live", ABC may have run it on tape delay, but it was effectively live for me because I didn't know the outcome. I also remember being stunned by the size of the biceps and shoulders on the GDR women. I'd been swimming for a few years by then, enough to have been to quite a few swim meets, and I'd never seen a female swimmer who looked anything like that.
