I moved to Jax just a few months ago and the first thing I noticed was how LOUSY the radio stations are. Nearly all are owned by Clear Channel and the commercial to music ratio is terrible. And in the mornings the commercial+talk to music ratio is even worse.
So I did what I thought was unthinkable while living in little Tallahassee, and decided to pay for radio. My travel time to any destination in Jax is much greater, so having good tunes is important. And I like to hear new music so I can choose what new MP3s to burn.
Anyway...I got XM. My brother, who is also here in Jax, has Sirius. So far both of us think it is worth it. I do get some signal loss in heavy tree areas, but otherwise it is pretty solid. Sirius has 3 sats rather than 2 like XM, and it seems that reception on my brother's set-up is more consistant. Sirius is more expensive though. It plays a bit more of the eclectic stuff that my brother likes however.