See these articles for some suggestions:

• Firefox says it's just updated every time it starts - how to fix

• How to set the home page - Firefox supports multiple home pages separated by '|' symbols

• http://kb.mozillazine.org/Preferences_not_saved

Before I received this reply, I discovered the about:config file and edited that. there are two startup related entries in there that listed the update home page. I just blanked them both. I still get the "looking for updates to my addons" dialog, but at least that forever damned Welcome page doesn't appear. I'm going to go through the Preferences_not_saved article when I get home and look at editing my user.js file and see if I can fix the rest of this.

I've also turned everything related to auto updates off. thanks guys!