Hello.....I lurk a lot, but this is the first time I've posted....hope I got this right.

I use an open D a lot (DADF#AD). It is very good for Irish and Scottish tunes and if you use a slide it can be pretty bluesy. I use a glass slide on my electric, but for the acoustic I prefer brass.

I can go back and forth between the D and a standard tuning pretty quickly with very little delay, but all that tuning and re-tuning is hard on the strings. If you're playing in front of people it is probably best to have two guitars....or else play all the open D tunes in one set and tune back to standard during the break.

If you like blues, allow me to suggest an open E minor tuning...it can be a lot of fun.

PS Capos are fine.....if you use one then yes, you can adapt more or less any tune to any open tuning.