Bad news first because people like to exaggerate and it has never actuallly been "bad news" as much as "less than optimal news". If it were really terrible, then they'd just sit me down and tell me reluctantly, adding any possible good news as an afterthought.

Plus, as stated many times, good news perks you up which I'd rather leave with than potentially having it taken away by bad news.

Bad news first. Otherwise I'd hear the good news and get excited then disappointed with the bad news. Heck I'll take the bad news and if it's too bad don't even tell me the good news. I don't want to know.

I always say "Good News, Bad News Time", and then tell them the good news if its more then the bad, or tell the bad first if its more then the good.

For example:

"Good News Bad News Time: The good is that I can give you your $20 back, the bad news is that it won't be until friday".

"Good News Bad News Time: The bad news is that we are all out of stock on those Razor Scooters... the good news is that we should have some in next week."

Something like that, you know? As for me personally? I don't really care either way.

My stomach drops when asked this question, the good news doesn't even matter much. I just want the bad news and I hope that the good news is more powerfully good so as to override the bad.

It never is.

Bad news.

Like others have mentioned, it's because of two things:

1) The good news can counteract the bad news.
2) If you end with bad news, you tend to leave the conversation on a sour note. If you end with good news, you tend to leave with a better feeling.

I really don't give a damn.
I usually put my emotions and judgments on hold until I get all of the pertinent information anyways, and then weigh in my thoughts and feelings, so its not like I would be particularly affected either way.
If anything though, what I really would like to hear last is the more important news, that way it is fresh in my mind.

I guess in most cases I would take the bad news first. My mom always taught me that no matter how bad your day is, it can always get much worse, so try to take at least one good thing out of each day. Its just for me knowing the bad news first, gives me something good to look forward to after the bad news is given.