I love the music on your show. However, one group I have never heard on your show and didn't see in your suggestions that I would like to hear on your show is the British band Muse, in particular, the songs "Uprising" or "Resistance" which have political themes. These are both from an album that came out last year and are pretty much my political inspiration songs of late. I don't know whether they are popular around the U.S., but Muse is huge on the mainstream L.A. based radio station I listen to. Their music has a futuristic sound to it.
I love Coldplay (also British, I know) but your show already has Coldplay songs sometimes. In fact, the theme song reminds me of Coldplay's "Let's Talk" song.
The suggestion to play John Fogerty's music is a good one, too. I saw him on PBS a year or so ago, and he had a new antiwar song, whose name I forget. I also found out that "Who Will Stop the Rain" which I used to listen to as a kid is an antiwar song, although I did not realize that as a child.