Somewhere along the line it seems like I downloaded one too many internal builds of Internet Explorer 7 and hosed my browser setup. Since I hate mucking around with re-installing, rebooting and registry tweaks I decided to use Firefox as my full time browser instead. Not only have I not missed IE 7, I've fallen in love with certain Firefox extensions like SessionSaver which recovers all open browser tabs and form content in case you have a browser crash. This has proved to be a godsend when I come in during the morning and our IT department has rebooted my machine due to some security patch. All I need to do is fire up Firefox and have all my open tabs from the previous day show up in the browser.
The only problem I've had has been with constantly being prompted to enter my username and password on every Sharepoint page I browse to in our corporate network. I had almost resigned to having to waste my morning trying to fix my hosed IE 7 install until it occured to me to search the Web for a solution. That's how I found out about the network.automatic-ntlm-auth.trusted-uris preference. Once I tweaked this preference, it was all good. ...Except for the fact that Sharepoint seems to use a bunch of Javascript that only works in Internet Explorer so I'm still going to have to muck with my Internet Explorer install anyway.
At least I can browse different pages without that prompt showing up all the time. I hope this information is useful to some other poor soul who's trying to use Firefox on an intranet that requires NTLM authentication.