I've got the usual Artist->Album->Song setup because I find that to be the quickest way for me to find what I want. Because I have so many items in the root (a lot of artists), I find the dial to be very useful, and I'm amazed at how well they did the acceleration on it. I find that one really quick spin can get me all the way to Led Zeppelin

Also in the root, I have ~Other~ and ~Jazz~ I believe. Jazz is obvious, and I keep it in its own seperate genre because I can more easily tell the player to ignore it on a full player search, and it would look wierd to have Gerry Mulligan next to Led Zeppelin

Well, that's my setup. I like it.