I have a lot of favourite black characters in DC who need much more exposure, or their own title.

Green Lantern (John Stewart): I'm a longtime Hal fan, but I've always loved John Stewart. There should be more than one Green Lantern title, there should be a few in my opinion. (A John/Guy team up series would be awesome)
Mr. Terrific: Micheal Holt, a notable improvement over the golden age one, and simply one of the coolest characters on the JSA today.
Vixen: Of all the Detroit JLA characters, Vixen is the one that really took off, to being featured in the JLA cartoon, to being a member of the Birds of Prey, her popularity has really grown over the years.
STEEL: aesthetically this guy looks so cool. I've always felt he had great potential to catch on if used correctly.
Black Lightning: Has definitely surpassed Geo Force as the most popular member of the Outsiders (Batman aside)
Bronze Tiger: You know your getting old when you can remember Bronze Tiger. Simply put, a really cool marital arts character, I would like to see him used a whole lot more.

Wallace West & Jackson Hyde, great young characters, they should being pushing them now, so in 20 years their fanbase is strong enough to jump from the Titans into the role of Flash and Aquaman, like Wally did for Barry.

I didn't see the excluding part of the thread so I botched my vote, thinking you left off John Stewart. On the current list I would have chosen Mr. Terrific.