Buckthorn when I can find a stave thats not defect riddled. Black locust when I can pull one off without chrysals. Elm would be a go to wood for sure. HHB although I've only made one from it to date I really
liked the way it worked. I like hickory cause its easy to find clean staves and I'll work hackberry as well.
To be honest I like 'em all and enjoy working with different woods. Even when I have osage (The King) on hand I'll still work on others too.
Man almost forgot to mention mulberry.