I've never really loved Ribbon UIs, but only because of PEBKACs around me coming to me whining cause they're useless at looking at something right in front of them. Why switching Explorer to a Ribbon UI sounds like a good move to me is because they're using it in other flagship products that actually sort of require and benefit from that kind of workflow. While Explorer could probably get away with a less able UI, the droves of PEBKACs that roam the planet will whimper and annoy slightly less if Explorer as the same UI as they see in other places. Old school PEBKACs will whine regardless, but new ones will not reach their peak crying-volume, thanks to decisions like this. I may loathe most things Microsoft, but really, I think they made a call that makes the average sanity level just a little better than if they'd done anything else. Now, if the MS Office team decides to make a totally new UI shortly after this, that'll be like the best self-trolling since Chris Crocker.