I voted Zatanna. To be fair, I don't know most of the characters (other than in name), but those I do are mostly associated with teams in my mind. Zatanna strikes me as strong and different enough (as in, the corner of the DCU she occupies) to carry her own book in a way few of the others do. But again, that's just the basic impression I've gotten, and were I more familiar perhaps I'd feel differently.
Deserve? To me deserve means she's obviously popular enough to headline, carry and maintain a high level of sales on a solo title.
Based on the above criteria I wouldn't say any of these ladies deserve a solo book with the possible exception of Power Girl.
DC needs to cancel Worlds' Finest, bring back Helena Bertinelli, and move her over to BoP. Then they need to call Jimmy Palmiotti, Justin Grey, and Amanda Connor and offer them anything they want to work on PeeGee again.
That would be great, I also prefer Bertinelli over Wayne.
Considering the current popularity of the Green Lantern line, DC might find some success with a Star Sapphire series. I mean, Red Lanterns is close to finishing out it's second year, and that's pretty much a one-note concept.
Yeah, a Star Sapphire series can be very successful.
Zatanna, I feel there are lot of things that DC can do with the character beyond what they're doing with her in Justice League Dark. I could see her acting as a detective of shorts for the supernatural and mystical areas of the DCnU. She could easily operate out of places like Gotham City, dealing with various cases involving magical creatures, people, and objects.