In class we listened to some Led Zeppelin, the majority of their songs had a slower downtempo sound to it which didn't seem to impair the use of heavy guitars which kept most of the songs from getting boring although some songs were ridiculously slow and long and didn't seem to be going anywhere .  The lyrics weren't the worst ever, but they definitely weren't the best. Needless to say I wouldn't mind just listening to the instrumental if they also made it slightly shorter. Overall, Led Zeppelin wasn't bad at all.