I'm not saying these will be my top five or even my first five because I still have a lot of life to live, and I'm certain more will come up, but I will definitely ask these five (and these are the odds I'm laying on the answers), in no particular order:
What's up with the six days of creation? Who's right? (old-Earth creationists-4:1, young-Earth creationists-15:1, other-5:1.)
Who is Melchizedek? (Jesus pre-incarnate-2:1; someone else-7.5:1)
Who really wrote Hebrews? And why was it such a big secret? I have my own ideas, but I don't know if I'd bet money on them. (Paul-3:2, Luke-4:1; other 2:1)
Who or what were the Nephilim? (Angel-human hybrids/mixed breeds-4:1; entirely human-4:1; entirely non-human-13:1; other-5:1)
Is there really a Bible code? (Yes, the code guys are right on-11:1; No, of course not, you guys are nuts-7:1; Yes, there is a code, but you guys are nuts anyway and haven't figured it out yet-Even).