Hi Esau and Nate,
Yes. DADGAD is my home. I got hooked on it when playing a lot of Celtic tunes. There's an awful lot of Celtic music in D and A which makes it a perfect choice. I also find DADGAD to be quite versatile for other music as well. I've worked on translating a fairly harmonically dense Brazilian piece to DADGAD and only found a couple chords that needed slight re-voicing. I do love the rich sound of DADGAD, and it's versatility, which is why I have chosen to stick with it as my standard tuning.
I have 9 sub-basses on my old Austrian HG. The tuner for the lowest string won't hold pitch, so I really have 8 sub-basses. I tune them (low to high) GABCC#EF#G. I find this instrument a bit fragile and difficult to play so it doesn't see much use. If I used it more I might play with the bass tuning a bit for different tunes.
My new Kathy Wingert HG, due around Christmas time, will have 6 subs. I'm looking at GABCEG as my standard sub-bass tuning. This is Stephen Bennett's standard sub-bass tuning except that I have an E instead of a D as I already have that same D on the 6th string of the guitar. This HG will also have sharping levers on all of the sub-bass strings. The way I'm planning to set it up will give me quick access to F#GG#AA#BCC#EFF#G. With that, I don't feel I'll need to play around with sub-bass tuning too much.
I've found DADGAD to work especially well in the keys of D, A, G, F, C, and even Bb. Of course, you also have access to all the relative minor keys and some interesting modal options. I would consider trying to get an Eb in the subs for something in Bb. This doesn't take into account using a capo which I enjoy doing as DADGAD sounds really nice capoed up a few frets for certain pieces.
If you are interested in staring to explore DADGAD, I would be happy to recommend some fairly easy Celtic pieces to work through. It is easy to get a beautiful sound out of DADGAD with very little work.