Wow! I did not expect this much of a response at all--thank you so much! Just a few caveats:
I can see that this sums up an understandable sentiment among quite a few of you, one which I have felt myself from time to time. However, I suppose I should clarify that I primarily want to teach. I really enjoy research, I just do not believe that I am innovative or brilliant enough to create something truly meaningful, at least not to the degree that would be demanded by a top research university, and I don't want to spend my career kicking out meaningless articles in unread field journals. I do hope to "give something back" to economics, of course, but I think I would be better equipped to teach and then work on research on the side. That was a long clarification.
Second of all, I do believe that it would be necessary--or at least highly preferable--to get a PhD even if I only taught undergraduates for the rest of my career. First, I think a PhD is a great signaler of how committed one is to the pursuit of education or ideas. I think the passion that is required to get a PhD transfers into teaching; I've seen too many (business) teachers coast into college with a masters degree and work experience and just suck at teaching. Also, I think having a deep, theoretical understanding of a subject allows one to be a better instructor, even at an elementary level (think teaching calculus without analysis). I would also need it to help students who, being more brilliant than I, would actually want to go on and get a PhD and contribute to the field on the research side.
And on a side note, I would be focusing on micro (and maybe applied 'metrics). I'm not really a fan of how...diverse macro seems to be right now, or how its taught at the undergraduate level.
Sorry this was so long--terseness is not really a strong point.