Saruman

Saruman, aka Saruman the White, was a buddie of Gandalf until he turned evil for no particular reason. He was once a 'wise and powerful wizard' but when he turned against the good guys he decided to burn a load of forests which made Treebeard angry. Treebeard launched a massive attack on Isengard, where Saruman lived, and annihilated his army. Gandalf arrived soon later, only for Saruman to take a tumble off the Tower of Orthanc and die when he hit the bottom. Ouch.

His buddy Sauron got a bit upset at this point, as he rather liked Saruman. Maybe he just thought their names were too similar. Speaking of similar, a trio of Saruman look-alikes formed a band called the Sarumen after the death of the real Saruman, and went on to be a bit hit in Middle Earth.