I upgraded to Pandora One and am happy I did. I use this instead of XM / Sirius. The desktop App is great, higher quality audio (192 kbps), zero interruptions (unlike XM/Sirius), plenty of skips, unlimited listening (I would max out each month at work). On AT&T you will likely need to upgrade to the 2GB data plan = $10/mon more (compared to 200MB @ $15/mon) but I was pretty much already at the 2GB level anyway.
It's $36 well spent IMO.