Service pack 1 of SQL Server2008 is primarily a combination of the three cumulative updates released so far, and has now been released as a public beta (or CTP to use Microsoft speak). Trying out the public ctp will enable you to apply all of these at once as well as doing providing a slipstream installation so you can do a complete up to date install in one strike.
The one useful new feature I did notice in the CTP was the Report Builder 2 is now a click once install from Report Manager.
Needless to say (but I will anyway) not for production yet! but if you want to try it the you can get it on TechNet here.