Jason,
It really depends...this is my second time going through the process and I can tell you that my first panel interview back in March was a complete 180 to the one I just had. My recruiter provided me with feedback on this most recent one and said I did outstanding, which is a relief...the panel asked me the following:
1. Why the Navy
2. What do you have to offer (I'm a lawyer by profession, so naturally, they asked why not the JAG instead?)
3. Current Events
4. How do you feel about taking orders from someone who is potentially younger than you, considering we'll be o-1s and it's likely that we could be subordinate to younger 0-2/0-3s, possibly even 0-4s.
5. How do you feel about deployment/is your signficant other/family onboard
6. Provide examples of leadership, both in professional/nonprofessional setting
Good luck, hope it goes well for you...what are you applying for? Is this your first time? How is the rest of your package coming? Hopefully we cross paths down the road in DCO or beyond