When I've asked DP's "what are your thoughts?", my favorite answer has always been "...well...what are YOUR thoughts?". But that's just me.
I hope by 'favourite' you mean you laughed him out of the room!
When 'interviewing' a DP, you're mostly trying to figure out if they're creatively on the same page as you, and if you can communicate and get along well with them.
I try not to meet until I've read the script, and I usually take my iPad with some examples of the look I'm feeling from the first read of the script. I generally chat to the Director(s) and Producer (if the Producer is there) about what they've done, and explain to them my background and experience. By this point, they've usually seen your reel, and are interested based on that, but I keep my reel and short scenes etc. on my iPad just in case (though I've never once opened them up during this type of meeting).
I talk about the visual and creative ideas I have for the script, what format I think we should shoot on, and sometimes we talk basic budgetary concerns - i.e. I might feel that a certain film would look incredible and work really well on Super 16mm, but they don't have the budget, so we start to look into other options.
I also explain the way I like to work, both in pre-production and on-set.
Most importantly, whilst all the information is important, you're wanting to build a rapport with the Director, as the two of you are going to be working very closely.
If you feel the DP you're interviewing is on a very different page creatively, and can't be reigned in, or is going to be difficult to work with, then you shouldn't consider hiring them.