I don’t know if the MOZ_NO_REMOTE workaround is still necessary for Firefox 2.0, but I do know I’m at the point where I want to run multiple Firefox profiles at the same time. I kept searching for firefox instances concurrently, but apparently I’m going to run multiple profiles concurrently, not instances. Oh, well.
I used to use IE, Opera, Safari, and more in order to separate out multiple logins to the same site for the different online identities I use (personal, work, anonymous, etc). I can’t live without Adblock Plus, though, so I need to run multiple profiles of Firefox now.
There are a few quirks, but overall it seems to be working how I want.