The Ferrari wordmark is very successful to me. The white is clean inside of the red text box and the line extended across the word from the top of the f guides the eye across. It also serves to unify the piece so that the wordmark can stand alone. I also like the Youtube wordmark. I think that white black and red are very powerful and clean colors to use together. The tube inside of a TV-like rectangle reads into the purpose of this website and gives it an artistic flare.
On the other hand, the Calvin Klein logo is unsuccessful to me. While it has done a proficient job at branding this wordmark, to somebody who does not know what Calvin Klein is it would be hard to organize the faint grey name with the big, bold initials. This comes across as very cluttered to me.