Going with Storm over Cyclops, but I think it will be close. Both characters have great name recognition. I think Rucka has a bigger following than Pak and is, respectfully, a stronger storyteller. But even if it is spinning out of a best-selling X-Book, Cyke's book is dealing with what's essentially a diluted version of the title character, while the hope for Storm's solo is that it will be a character readers have loved for decades getting some spotlight time after multiple upheavals in her life. Nightcrawler's going to trail the pack a bit and it will probably be Claremont that brings the interest. Making Kurt's return the focal point of a new book didn't exactly set the charts on fire with Amazing, and I think the follow-up series will reflect that as well. Not that Kurt isn't a great character, but when was the last time he was allowed to show that? Maybe Ellis-era Excalibur? There's affection there for a lot of readers, but I don't know how much excitement.
Of course, all that said, I pre-ordered Cyclops and have Nightcrawler and Magneto on my pull list. Storm is going to have to be a shelf read before I decide anything, since I'm not gaga over the creative team.