Batman, issue 0 just came out this week, literally no better jumping on point, & Batman is easily one of the best (if not the best) superhero comic in all of comics right now, Synder & Capullo are possibly the best creative team I've ever read & are killing it on Batman, Nightwing would be another solid choice, Flash can be good, as can Swamp Thing & Animal Man as well.
Aren't there like half a dozen books featuring Batman and/or one of his sidekicks?