Saw the Robert Earl Keen show at the Austin City Limits music festival over Sept 14-16. Great show, Keen couldn't quite stop grinning thru the entire thing. He's part folkie, part rocker, and part Jimmy Buffet.
The Robert Earl Keen MySpace page has a couple live cuts that are worth a listen. "Feelin Good Again" is a great example of his Texas twang; he's not terribly introspective, but has a nice Austin-style sound that went down really well at the festival. Also at the concert (but not on the website) was his rock version of "Long Chain On", originally done by Peter, Paul, and Mary.