If you're talking only about desk organization I'd go for order. My reasoning is that order is a proven process: you first organized your desk and saw how to organize it to be most efficient. In doing so you created some order.
This all go with the quality of a good programmer: good analytical skill (you saw how to places things to maximize efficiency), attention to details (by placing all my things correctly I save ms of time when searching for things), seeing patterns, etc.
This do not means that an unorganized desk is necessarly a bad one (he can be a genius) but I'd say order as an advantage and it's code, while maybe not as clever, is probably more organized.
Personnality-wise I'd say it is different and will probably vary according to your taste but I think that chaotic personnality are usually more creative and this might be something you might be looking for in a programmer.
So well, to conclude, I'd say it is relatively subjective first, and worse it depend on the situation (a chaotic desk is not the same as a chaotic personnality) and more than that on the reason behind the order or chaos.
Exemple: I can have an orderly desk because I have a lot of attention to details and just notice that by placing my notes just there it makes space for my cup of coffee just there and just there is just the perfect place not to spill it and be able to reach it easily at the same time .. or I could have an orderly desk because that's how my parents told me to do and I just never questionned them.
I think that we can conclude that, even if both situation is an orderly desk, it is not the same at all to check for programming ability.
So in short, do not look at order and chaos by itself but on the reason behind that order and chaos and I think that's the principal thing to look for. If your reasons align with programming quality then who care what others think.