Some favorites of mine in addition to those who may not have been mentioned already (most of these I don't have names for and I apologize in advance):
Stuart Shulman (SCV '02-5): his looks, professionalism, and intensity make him the most mature-looking DCI drum major I've ever seen.
Glassmen 2002 Drum Major: he made the wink cool long before 2016.
Madison Scouts '97: pirate flag + camera during sustained chord (need I say more?); still cost them a 0.1 penalty but totally worth it!
Cadets of Bergen County '97, Blue Devils '99 & Madison Scouts '04: look like they're about to go super saiyan at the very end of their shows.
Madison Scouts '75: My man nearly falls of the podium throwing his hat towards the crowd; if that isn't hype I don't know what is.
Charles Stewart (Bluecoats '94): Sunglasses + chill= swag2
Stacey Slack (Bluecoats '98): That dance on the podium during "Summertime" is unforgettable.
Brandon Barrometti (Cavaliers '02): One of the most humble and professional drum majors I've ever seen.
"Murderer" of Will Pitts during "Spartacus" (again sorry on missing name): Great dramatic moment and very engaging in his own right.
Norman Dziedzic (Cavaliers '85-7): It takes a special kind of drum major to conduct 2 time signatures simultaneously during "Variations on a Korean Folk Song"; same goes for all SCV drum majors who conducted "Young Person's Guide to the Orchestra" over the years (even The Cadets had to use 2 drum majors on the main podium during their 2001 rendition).
Jonathan Powell (Blue Stars 2008-09? possibly more): Intensity through the roof.
Michael Hayes (SCV '98-9): Personified the corps' hunger for a title those years.
Cadets '89: Catching red flag such a striking exclamation point on end of "Attack on Rue Plumet".
Becky Saddlemeyer (Star of Indiana): You could tell all the way from the stands that she had a heart of gold (at least I think so).
Emily Neuendorf (Colts '97-9): Conveyed such genuine, palpable emotion on the podium.
Reggie Brown (Spirit of Atlanta '86): Can I get an amen? Hallelujah!