@TylerM: what do you hope to accomplish with the PhD? And remember Dijkstra’s pithy statement that computer science has about as much to do with computers as astronomy has to do with telescopes: at its core, computer science is a branch of math that deals with computability.
The PhD is a long, grueling slog. It’s hard work leavened with brutal politics, for very little money. Practically speaking, you’re sacrificing 6 to 10 years of earning potential in exchange for that certificate. The starry-eyed romantic view is that the PhD is some kind of certificate of worthiness; the only place it really matters is if you’re looking to be a college professor.
And even then, the number of PhDs awarded each year is (depending on field) anywhere from twice the number of available openings to 20 times the number of available openings. So you’re sacrificing 6 to 10 years of earnings (and remember, you’re planning for retirement, so those early earnings plus compound interest are important) in exchange for a 1 in 2 to 1 in 20 shot at landing a job. Of course, if you don’t get a real academic job, you can always work as adjunct faculty for $2000 a class.
And so if you’re not looking for an academic job, I’d say don’t bother with the PhD. If you find you need it later, you can always go back to school for it, and by that point you’ll have enough of a frame of reference for it that you’ll benefit that much more.