hope this helps:
love: i saw them in 2002 in philly, and in 2003 at the birchmere. both shows were amazing, and arthur lee's voice is still powerful and emotive. i wouldn't miss an opportunity to see love if i were you. take note, however, that i am biased, since "forever changes" is my favorite record of all-time, and if love stopped making records after "four sail," they'd be my favorite band of all-time.
the zombies: with colin blunstone and rod argent. if blunstone's involved, it will at least be good. i have not seen any variation of the zombies live.
living colour: saw them at the 9:30 in 2001. it was a good show, but a bit wanky. you won't miss a whole lot if you skip out on this, especially since they'll probably be back next year anyway.
public enemy: i've never seen them live, but i think they're past their prime. terminator x being there would make me think twice about seeing them, but my intuition tells me that it won't be that good. i doubt they'll even come close to the genius that is "fear of a plack planet."
verdict: go see love.
as for me, i am hoping to see love and at least some of the zombies. i have to run to the warehouse to check in on bloodthirsty lovers that night, too. what a full night of music in DC.