I wanted to put some sort of content on here quickly, so here is a link to my teams blog which I wrote last year about a common question asked when it comes to servicing the operating system. "Why is the \Windows\winsxs directory so large?" The short answer is that it is really a "flat" of your Windows installation which means that its all of the files needed for you to use Windows without the need to put a CD\DVD into the drive every time that you need to add a new feature or update a file.
For more information on why its the size it is, see my old post here:
Also, check out some of the other cool information my team has regarding topics like clustering and DPM.