ActiveX is the road the exploits ride in on. If any website depends on ActiveX then Firefox, Mozilla and other browsers may fail. There is no cure planned since it's asking for exploits that IE allows.
For what few sites that don't work with Firefox, Mozilla I'll use IE. But on my list that's just one which is Windows Update.
I can't seem to login to any of my MSN related websites, such as My MSN, or MSN Hotmail. Every time I type my email address and PW into the login box, I get "Error establishing an encrypted connection to msnialogin.passport.com. Error Code: -8075." It is set to accept cookies. I haven't used Firefox too much for this reason, so I admit I'm not too savvy yet.