Over on the MediaTemple Blog, I talk about some logical possibilities for how you might arrange the declarations within a ruleset. Personally:
I'll admit, I traditionally haven't had much of an opinion about the ordering of CSS properties. I just add what I need. I think they end up largely "grouped" by related things because that's just how my brain spits them out.
While writing this, I looked into CSS Comb again, and I'm starting to be convinced this is a good idea. I don't know if it's worth the tedious work of manually organizing properties, but I can see the advantages of code that is meticulously organized, so having a computer do it seems like a good idea.