day-day:
Yup. So if you never, ever, plan on leaving the country, EVER, over the next ten years, don't do it. I said I could appreciate weighing the cost vs. value. I just personally can't see going 10 years without -- at the very least -- cruising, and I think the passport is much easier to deal with at the port than birth certificates. Your experience at check-in is only going to go as well as the person that's helping you. And once in a while you're going to get someone that does not know what they're doing. "Is this birth certificate a certified copy? It doesn't have a raised seal!" A new person may not know that your county no longer issued raised-seal certificates. Will it probably get worked out eventually? Probably, but you'll have spent a lot of extra time and stress, and there are no guarantees even at that....No questions with the passport. If, God forbid, something should happen and you're stuck in Belize or Aruba or someplace, I imagine dealing with getting back into the country would go more smoothly with a passport rather than a birth certificate (especially in today's travel climate).
No doubt my experience is different than someone else's....but for me, just knowing that if a friend comes up to me and says "I find myself with an extra ticket to (insert foreign country name here)" that I can pack my bags and GO, is worth it...*s*