I've always been a big fan of DaisyDisk — I used it just today to free up a whole bunch of space — but I thought I'd give FlameGraph a go. It helped me free up 2.2GB of totally valuable space (this is a 120GB MBP - brutal) with 2 clicks instead of the 6 it would have taken DaisyDisk.

DaisyDisk essentially shows the exact same info as FlameGraph — if you 'unwrap the wheel' it's exactly the same! — but the latter makes the excellent design decision to label many of the bigger directories on the graph, rather than just a single level in a key. Often, when you're looking for big directories, you're really looking for big unnecessary directories, and being able to see way ahead really helps.

I'm sure there are arguments as to whether it's the "best" representation, but I'd contend that it's the most intuitive.

It's probably the first OS X App where I bought licenses for the whole family; they all benefited from it.

I probably should have made more emphasis that it is the "best" that I personally have found.

Mainly in terms of ratios - I think my mind perceives size ratios better on a circular pie style presentation (as DaisyDisk does), rather than stacked blocks as most other utilities use.