My Own Summer by deftones is in Drop Db tuning, so thats one song out of the way :) .

I drop my guitar down to be at leasttwice a month or so to play a couple of Throwdown songs, Damageplans "Crawl," And a few songs off of Slayer's more recent cd's (which is the B tuned to standard at that pitch.) The bottom strings buzz like crazy, but with headphones and distortion, I don't here it. When I tune that low I usually leave my first 3 strings in standard since the songs I play don't use them, so I geuss that helps with any truss rod issues. What I'm doing could be bad for the guitar, or I could be okay for now, but its up to you. I haven't had any problems yet (knock on wood.)

I use 10's and it sounds great, not like rubber bands. I've tuned to Korn's tuning (Use ADGFAD since mine's a 6 string, not a 7) and that sounds like rubber bands cause of the light strings.