I don't retune. I use the Keyser "Drop D" capoes a lot, for playing in E (or F or G, using the drop D capo 2 frets above a "normal" capo. They're also good for A or Bb or B or C, using G chords. (You get a very nice 1-5 bass by just playing the low E, in normal G chord position, fretted at the "third" fret, then lifting off and playing the same string open at the 3 beat.)

I like to play in DADGAD, but I prefer to leave a guitar tuned that way. Some guitars - those with exceptional "ring" or sustain - sound better that way than in regular old fuddy-duddy tuning. I used to have a Seagull 12 that was great for that, but I got tired of tuning 12 strings and sold it. Now my Taylor 414 serves that purpose. This also gives you the option of using heavier strings on the strings that are tuned down.

I thought it would be fun to get a Takoma "Papoose" (they're made to be tuned five frets high, A-to-A) and tune it GDGCDG, to be able to use DADGAD chords in more keys, but I probably wouldn't use it enough to justify the cost...

Peter.