LOSC and Letters are always going to be classic solo Butch. Those recorRAB are brilliant. Rise and Fall, even though it's a totally different sound, every song on that record can grow on you in a different way. It's the perfect sound to drive with the windows down. Very fun album. The M3 stuff is amazing as well.
I think his new record, Sycamore Meadows, is going to be possibly his best yet. I've only heard the demos and recordings from his shows on youtube, but his new songs sound AMAZING. He did release two new tracks on iTunes (and on his myspace) not too long ago. Ships in a Bottle is so good.