Reason and Rebirth are great examples of skeuomorphism, Apple's are pretty poor.
No, just no. Skeuomorphism for the sake of eye candy is just dumb, especially in real OS apps like the contacts and calendar app. In toy OSs its a little more excusable because there is supposed to be a tactile experience using a tablet or a phone, but it is still annoying. I used to use ical and address book all the time but when they switched over to the new look i just used google, i only open those apps when I have to. On the other hand, some of my favourite apps are based on their skeuomorphism, Reason, The Moog app for iOS, the Roland apps for iOS and Rebirth for iOS. They are all seriously eye candy, but it serves a purpose, rebirth looks like a 303, reason's modules look like a real world device adn behave in a similar way, right down to being able to turn the rack around and getting to mess with the wiring. yes, it is a waste of space, but in the case of these apps i have found it to be very helpful. Imagine if adobe made the RAW plugin for Photoshop look like actual photo tools with a the developer and chems and all of the other obnoxious things that goes with developing real film. I use the computer to have a clean fast UI not to have something that makes me feel like i am using a paper and leather address book or calendar it is unnecessary and tacky.