I'll tie in two of the above thoughts.
First, diversity in life is the key, indeed, LSH! Musically, the artists I stay with for a long time have that diversity -- and it not only keeps ME interested -- it also keeps them around too! As an example, I heard a recent Nick Lowe album about a week ago. This guy has been around as long as Gord, and he's gone from an obnoxious rocker (Basher) to country to balladeer! Take a look also at the older players on the British music scene. A lot of the names from 30 years ago are still touring and strutting their stuff (Al Stewart, Bert Jansch, Richard Thompson, the list goes on...)
Second, I am also one of those who hears something new, and then mercilessly plays the life out of it. In my computer operator days, when I worked shift, my shift partner and I used to bring in one tape or CD - yes, ONE - and play it the whole night through. Again and again and again. Then after a few weeks we'd tire of it and discover something new. In fact, she passed by my desk the other day - we both have different jobs now - and she said that she's found a new band and she's doing it again! They are called Scissor Sisters, and they do rock, pop, dance, glam rock, and electronic. I gave them a listen and it's fun stuff. A few of the songs were not to my taste, but they're to be enjoyed, not to be taken seriously. Again, this all ties in with LSH's point of diversity. They've put the diversity on one album, not through a career of thirty years!
Oh yes, and my overdoing it habit with new things I like is not just limited to music. Maybe one day I'll tell you about the time I discovered Green Tea...
David in Sweden