I don't claim to be in RFielding's league (except in baseball, these days), but we have been nurding around in open D tuning -- so here is a separate thread on open tunings. Open season.
The seed for me in this was Bod Dylan's obsession with a few neat details in open D, which he uses in Tangled Up In Blue, Simple Twist of Fate, Shooting Star, and a zillion others. The chords he uses are:

D 054000
Dmaj7 044000
D7 034000 sometimes 030300
G 020120
Gm x05450
A4 x42000
A? x02120
Bm x20020

The bass run down the 5th string and occasionally onto the 6th is infinitely useful. He also has these great chords:

Em7 222100
F#m7 444300

Also worth noting is the really nice:

Em9 or something 005554
This can go up and down almost everywhere.

yours, Peter T.