I would really like a classroom where everybody had enough personal space. I would also like a place where children could learn in the best way possible for them. Not everyone does well sitting in a desk all day. Sometimes kids need to stand or laydown to do their work.
Having enough materials for every child that is suited to her or his needs would also be important. I know you said "not just 'things'" but that can be the dividing line between a good class and a "bad" class. If students don't have the right kind of pencils or lined paper it may be very difficult to be sucessful. Also, for younger students, it is very important to have a lot of concrete materials so that they can really internalize ideas and concepts.
An ideal classroom, to me, also has an equal number of boys and girls, an equal number of high achievers and challenged students, children that listen and follow directions, and that have parents that support me in my task of educating their children in the way I was trained to do.
I hope some of this is helpful. I really got lucky this year and have most of the stuff in the third paragraph. I feel really blessed.