Also got daisy disk.. not used yet but will
Since joemike mentioned my name relative to GrandPerspective/DaisyDisk somewhere, I'll respond here, since you've mentioned DD.
I'm running both GP and DD, and while GP's output is awfully pretty and very easily digestible, it doesn't give as much detail as DD does, although DD's output is not the least bit clear or explicit.
Bottom line is that I use one or the other depending on what I'm looking for, so I don't consider either one more useful than the other.