When Marvel VP-Executive Editor Tom Brevoort answered the following question on his Formspring account this weekend, he answered a question I've had for a long time as well:
what are Marvel's most popular selling comics in bookstores?
As a group, the Ultimate titles.
Veteran chart watchers have no doubt tracked the slow decline of the Ultimate line -- or Ultimate Comics, as they're currently called on their covers, if not their indicia -- for years now, something the Ultimatum event and subsequent title revamps and relaunches didn't really stop. Moreover, several of the big selling points for the line when it was created -- a lack of years of convoluted continuity, more timely cultural references -- necessarily get diluted as the books age. Marvel has long justified the continuation of the Ultimate Universe by referring to it as a place where the "rules" for the mainline Marvel books do not apply, a place where some of the company's biggest writers (Bendis, Millar, Loeb) can run wild. But if Brevoort's right and comics branded with the "Ultimate" moniker have a leg up in the bookstore market, that's probably reason no. 1 why Marvel still has the books' back.