Yesterday, I helped an NGO move from Windows to GNU/Linux, using Ubuntu 9.04 (Jaunty Jackalope).
It got me thinking "what would be the next codename? What animal names or nouns are there with the letter K?" At some point I realized it was Koala and searched and found the next codename is Karmic Koala. I love Koalas!
I started thinking of much later releases, and I thought that by the time Ubuntu reach the letter P, it will be a really hardcore GNU/Linux distribution and will bring GNU/Linux usage to insanely high numbers, and thus all free and open source software.
My suggestion: when you reach the letter P, try the codename Proud Penguin. It can be an adjective or it can be a noun and there's hell of a lot to be proud of!