I'm the proud owner of a Martin D28-CW (#103) that I bought in December of '07. I love this guitar and see it as a lifetime "keeper". Since I got it, I have been experimenting with different kinds of strings to best bring to life its awesome tone. So far, I have tried:
1) Elixir Nanoweb phosphor bronze mediums - decent tone, very long-lasting.
2) Martin Bluegrass 80/20 bronze medium / lights - good to very good tone (probably even better in true medium, which I haven't found locally) and reasonably long-lasting for a non-coated string.
3) Ernie Ball titanium RPS coated mediums - somewhat "thin" tone initially, but played-in to a surprisingly rich, deep tone for a coated string. Some of the best treble tone and longevity of any strings I've ever used on any guitar.
4) D'Addarrio EXP phosphor bronze mediums - very unpleasing dry, brittle tone so far, but just put them on 2 days ago, and I haven't played as much as I'd have liked to.
I've gone with the longevity of a coated string because my hands get very sweaty, but I somewhat lean toward non-coated strings on this guitar for a more bluegrassy tone. Any suggestions? I've thought about ordering a set of the Tony Rice signature D'Aquisto strings, has anyone tried them?