Global pre-paid SIM cards

Do any of you out there have experience with global pre-paid SIM cards for tri-band GSM phones? If so, I could certainly use some advice. I am looking for a card that will allow me to use the phone in the various areas I frequent (Taiwan, Indonesia, Ecuador, Bahamas, etc.), but I haven't found any that are that expansive in their coverage.

I've just discovered that Verizon works in Taiwan, but the website says that it costs $0.69 for roaming, plus rented carrier charges. I'm afraid to use it.