Server Core is lean and mean but what can it be used for aside from sitting behind your infrastructure? The biggest new thing is IIS, specifically server core can now support asp.net websites. I think this is really useful as web servers need to be secure and increasingly highly available.
Server core and IIS 7.5 (the version that ships with Windows Server 2008 R2) do this by having a very small surface area, which needs to be patched left often, and provides less to attack. I did notice that there isn’t too much out there on what’s new in IIS7.5 but I will leave that for another post.
However I do have a video showing IIS 7.5 running on core ..
BTW the SQL Server 2008 database engine will also run on server core as does the current beta (CTP2) of R2, but this is not going to be supported, which I think is a great shame as it would get the same benefits and possibly run even faster.