I don’t really have one true favorite for DCI; it changes from year to year depending on the show. The ones I look forward to seeing are Spirit of Atlanta (have friends there), Cadets (have family connections within the corps, so I get free stuff. I’m also from New Jersey so, ya know, have to root for the home team, I guess), and the Boston Crusaders (my parents met through that corps so I’ve sort of been brought up as a crusaders fan.).
My favorite show this year was SCV’s version of Les Miserables. I’m a sucker for anything Les Mis..
As for DCA, my top two favorites are the Sunrisers (again, parents are alumni of this corp, my father is also in their Hall of Fame, class of 2003) and Fusion (the corp I want to join at some point).