I like open E. Its the tuning for The Black Crows She Talks to Angles. A really fun tuning that is pretty easy to get the hang of with out much effort.
My fav is a variation on DADGAD, DAEGAD down a half step. Written 3 songs in this tuning so far! Also if you like cool tunings, check out one of my all time fav guitarists Don Ross' webpage. If I'm ever in a rut, randomly picking one and dicking around in it is fun