While this probably won't affect your 'crash' situation with Firefox and Verizon, I'd just like to add a comment or two about what can go wrong with Firefox (maybe other browsers) and the Verizon web site. I'm now running 8.0 on both the PC and the Mac, but not before I discovered why my Mac FF version 8.0 kept hiccuping and couldn't connect MyVerizon.
I started by disabling the add-ons I believed could be causing problems (Ad block, Cookie Culler and https Everywhere). Bingo! The EFF version of https Everywhere was the culprit on logins with one VZ address, and logouts only with another. When I went back and loaded the same add-on on the PC, it too coughed up fur-balls and wouldn't let me connect. I'm still annoyed with 8.0 on the Mac for taking away the PDF reader many of us depended on for a 'normal' view of these docs, but (all things considered) it works as advertised ... so far. Hope this helps someone! 
