I would love to hear other aikidoka's opinions, coloured belts or not, hakama at black belt, position on the tatami. What happens in your organisation and why?
At my primary dojo we wear hakama at 5th kyu, no colored belts, and we line up in no particular order. At the Shodokan dojo I trained at we wore colored belts (mine was white), no one wore hakama, and we sat according to rank. For the most part these things don't make much difference, in my opinion...they're up to the taste of the organization. I was told by my Shodokan instructor that because their system is so highly structured, it makes it much easier for visiting teachers and students to know at a glance the general abilities of the people around them. Personally, I kind of like the idea of not having it being made so obvious. It doesn't really matter much one way or the other though. I think, like most things, it's not so much one way or the other as much as what you do with the way you choose.
When in Rome...do as Elaine does
ps-there's a great thread by the same name as this one which I think has quite a bit of input if you're interested in looking it up.