Actually one of my favourite chords (and perhaps the most useful moveable chord of all is this Bb(6th) position.

Thumb covers both 6th and 5th at the 1st fret. Ring finger barres 1st, 2nd, 3rd, and 4th at the third fret. If you play all six strings it's a Bb6, and if you don't play the 1st it's a Bb. Love that chord and use it all the way up to the 6th or 7th fret.