I've gone through a number of musical phases in my life. As a teen/high-schooler I was very much into grunge rock, Soundgarden and Pearl Jam were by far my favorites, but I also liked Alice in Chains, Nirvana, etc.
By college I had gotten into classic rock and many of the names that have appeared in this list already, Zeppelin, Pink Floyd, Cream, Hendrix, etc.
Nowadays most of the music I listen to is a little off the beaten path, which I can't recommend enough that people explore. There is a lot of really good music being written by guys, gals, and bands and because they play smaller venues they tour more, tickets are cheaper, and they are far more accessible.
About a year ago I went to the record release party for a San Francisco musician, Chuck Prophet. People showed up piled in a bus and did a tour through SF at night drinking Southern Comfort from the liquor store in Haight Ashbury that Janis Joplin used to frequent.
That's my over Chuck's right shoulder caught mid sneeze, we ended the night with performance of the new record.
http://www.youtube.com/watch?v=lG3F9ETjR5sAnother one is Alejandro Escovedo out of Austin Texas, Alejandro came up in punk music, opened for the Sex Pistols, lived at the Chelsey Hotel in NY while Sid and Nancy were there and had a few different bands before striking out on his own.
http://www.youtube.com/watch?v=kSlas3I06jgHe recently reformed one of his old bands, the True Believers. Once described as a marching army of guitars, I think they were one of the best rock bands of the late 80's. It's a shame they never gained more notoriety.
http://www.youtube.com/watch?v=kk4u0eiyyXk