I'm having the same issue, but changing that setting didn't work. In fact it was set to ring only already. I switched it to another setting and back, but nothing. I really don't need my phone saying, "Verizon Wireless" every time i get a call.
Edit: Looks like it does it on start up as well, and she also announces when i lose service as well. Still though if anyone knows a way to shut her up I'd love to know.