First is Brown v Sanders, a death penalty case from the 9th Circuit. The Court overruled the 9th Circuit (yeah, shocking). It is also the first 5-4 decision of the Roberts Court, with the Chief joining Justice Scalia's majority opinion.
Second is Volvo Trucks North America, Inc, v Reeder-Simco GMC, Inc., a case involving price discrimination. I listened to the audio of the oral arguments for this case. It was the first audio of Chief Justice Roberts that I could find, so I suffered through it. Sorry, the case itself wasn't very interesting. It is a 7-2 decision, with the majority written by Justice Ginsburg and a dissent by Justice Stevens joined by Justice Thomas. Interesting vote.