So far I have four players interested: Scotley, Shayuri, J. Alexander, and kinem. Near as I can tell, kinem is the only one with a preference (Council of Thieves). Anyone else have a preference? Would help if I had a ranking order. Of course if you are just happy with any of them, that is fine. Still, I can tell that each one of them has a specific type of flavor to the campaign.
Rise of the Runelords offers a mix of urban adventure, wilderness exploration, and old-school dungeon-crawl, with some nefarious villains and recurring NPCs.
Curse of the Crimson Throne has lots of political drama mixed with urban adventure. It also introduces a mechanic for Varisian fortune telling, which might interest some players.
Second Darkness deals with a threat to Golarion of truly epic proportions, with battles against drow and lots over overland and oversea adventure.
Legacy of Fire is an Arabian Nights-inspired AP with a desert theme and lots of travel involved, exploring new lands and discovering new dangers.
Council of Thieves is largely city-based, with many urban adventures and lower-city dungeons. It is also rife with political intrigue.
Kingmaker is a war-based AP, and sees the PCs dealing with much more than the typical dungeon-crawl. The PCs are explorers and mercenaries tasked with a wide variety of missions such as laying down settlements and leading armies.
So there you have it in a nutshell, without giving too much away.