I've been having a look at Windows Server 2008 clustering and the first thing I can say is... wow ! Setting up clusters, adding additional nodes and setting up clustered resources is far simpler than before, and the cluster validation tool means there is no more need for the HCL. Clusters can also be configured so that the quorum is not a single point of failure, which increases resilience. The GUI is much cleaner and intuitive than previous versions of the Cluster Administrator, which makes configuration and administration a lot easier. There is more information on Windows Server 2008 clustering improvements here.

If you want a closer look, there is a Windows Server 2008 Failover Clustering virtual lab available which goes over some basic clustering scenarios (but not SQL Server clustering I'm afraid !!)