Pop up RPG book? Hmmm...
Well, I didn't think the Serenity RPG would get any love, especially since Josh has panned it in the past (episode 1?), but I have to put my vote in for that. Yes, it's not as elegant as 3.x, but it's good for what it does. The biggest problem that I see with it, is that you have to be willing to fail. If you look at the series, most of the characters fell flat on their faces at some point and played the rube (Zoe's about the only one I can't remember playing the fool). If you can get over that, nay, actually embrace it, then it is loads of fun.
Of course that's easy for me to say, since I played a mix of goofy Jayne and Chet (from Weird Science)...
I don't remember this love for Savage Worlds at Gen Con, is this a recent phenomenon? I'll put in a vote for 50 Fathoms (a Savage Worlds setting book) as a decent pirate-y setting with spellcasters thrown in. A few kinks, but they were probably ironed out in PotSM if you wanted to combine the two.