ehh, you dont have an all of the above! lol, many choices
16 players - For complicated tournaments, ones with ALOT of rules so your people can be specialized, even so, i dont like doing this number because i feel like im not working hard enough
-Ive only done 2-3 at this number
17-32 - This is a good size for an organizer who wants to try a good quality tournament without all the headaches of the larger size
-about 2/5 of my tournaments have 32 players
33-64 - right around half my tournaments have been between this number, this is a size that fits nice with me, they take longer overall, but I like 64 player for the quality of it

-over half my tournaments
65+ - a pain to control, any organizer will tell you that

my 512 man one shot one kill was HARD even with the quick format i gave it. Even so i may one day WAY down the line try it again, other then that one... i dont think ive done any more over 65
-1 tournament