It may seem trivial, but we all spend a long time looking at it, it it needs to be functional and obvious where the "point" of the pointer is.
I use the standard OS2+ raised red pointer, and my busy pointer is a custom "Zzz" design, which pays homage to the OS1.x default while being updated to 2.x design (it fits in quite well, it should be the default IMHO :-))
So.. what does your mouse pointer look like?