IE is a sinkhole of security issues. Any self respecting Business would NEVER use IE for that simple fact. Compatability issues are much less of a problem than liability issues.
BTW, Chrome > Every other broswer. For serious.
While somewhat true, FF is not faster than Chrome or Safari (or anything that uses WebKit) because of it's threading capabilities. Also, instead of installing a bunch of unnecessary add-ons that will bog down the computer's memory, why not make a HOSTS
file and be done with it all together? Sure it's ever so slightly more difficult, but it also improves security dramatically regardless of the Browser.
Firefox is a slow memory hog. Chrome is fast as all hell and seems to be way more productive to me. Especially with it's built in search functions and the like.