If you've looked around for books on Windows Server 2008 then you know you have choice. I've done the searches, not just for 2008, but for 2000 and 2003 before it. But for any version I look out especially for the Administrators Companions, they form the core of my reference material and have helped on numerous occasions in the past. So I would really recommend starting with this one and then supplementing it with the Resource kits as and when you need them.