FREE MUSIC. No, seriously ... and it is legal. Apple is offering free music through their iTunes Music Store (iTMS) as celebration of iTMS one year anniversary.
If you have been looking for an excuse to try iTunes ... consider this your excuse. iTunes also had a major version update ... 4.2 -> 4.5 featuring iMixes (user playlists with a voting/ranking system), Party Shuffle (hot songs, more often), Apple Lossless (CD Quality sound, 1/2 size) and more!