Sir Lance-lot has returned, and tomorrow will reclaim his fortress from this barbarian invader. He writes: "Thanks for blogging for me, though I hope you haven't scared away potential future researchers."
Let me state clearly what I think. The greatest perk of being a scientist is never having to doubt the value of what you do. If someone who fed starving Ethiopians, or rescued baby seals from oil spills, asked me how I justify spending my time proving complexity theorems, I might have difficulty answering; eventually I'd mumble something about basic science (along with art and music) embodying the highest aspirations of civilized humankind since the age of Democritus, and therefore being worthy of pursuit even in the face of palpable suffering. But if some regular schmo -- a sportswriter, or consultant, or homeopathist -- demanded that I justify what I do, I'd laugh in his or her face.
Other benefits of a research career include the freedom more or less to choose your hours, the satisfaction of being "the person who discovered such-and-such", the opportunity to inspire students, and copious expenses-paid trips to conferences around the world. I won't dwell on the downsides of being a scientist, both out of deference to Lance, and because the downsides are obvious to anyone familiar with cultural stereotypes.
The point I want to make is that for me, both the benefits and the downsides are irrelevant, because I can't even imagine not doing science. Having once tasted it, I couldn't go cold turkey any more than a heroin addict. What if someone solved one of my open problems, or emailed me with questions about a paper I wrote? Would I ignore that person, just as though BQP/qpoly and NISZK had never been part of my life? I mean, obviously I'd be happier were I a self-assured ignoramus who majored in marketing and mingled on the beach -- but then I wouldn't be I; I'd be a different person.
In summary, then, you should pursue a research career if and only if science to you is life's kth greatest pleasure for some k=O(1). Thank you for reading.
[Addendum: Here O(1) is intended in the physicist's sense, not the computer scientist's asymptotic sense. You only live once.]