Personally, I think the color muting is cosmetic at best or worse. It's nothing really important to me. As for the vertical Close, Minimize, Expand buttons, I love it. I hope they implement that across all applications. Get rid of the title bar, in almost all cases, it's wasting my precious vertical screen real estate. If I've opened an application, I know what the app I'm looking at is, if not, I can see the name in the menu bar. Get rid of redundancy. Ping? I signed up, but I won't use it except to see when my fav artists that are using it announce a new album for sale. I can't be bothered to update my facebook or twitter 90% of the time as it is.
My only disappointment is the new iTunes icon. I disagree with some, because to me it does fit in with the randomly designed other dock icons. However, this is Apple's music, movie, tv, book, app store. They could have really emphasized the multimedia store as it has become. Did they decide Windows Vista was a great icon to emulate? I don't know. Maybe it just hasn't grown on me yet. I am glad they removed the CD icon that was cool in the 90's era, but the new icon is very uncreative. I guess it's safe, but now they have to live with this icon for awhile and it doesn't stand out to be taken notice of at all. At least I like blue.
Now just bring on iOS 4.1! I guess I'll continue to wait patiently for a better notification system in 5.0.