primarily they stick with tuning the bottom E 1 1/2 steps down, and dropping the rest of the strings a half-step only. ergo Vinnie tunes his bass like so - Db Ab Db Gb
As far as i know, they usually use Drop B. Or atleast they use it a lot. Which means you tune to B F# B E. But yeah, Sevendust rocks. The put on a great show too. This last concert was one of the best I have ever been to.