I really like my deflecto cup holder.  It attached to my standing desk with ease and it holds large and small sized cups and bottles steadily.  The colors aren't the prettiest, but from a utilitarian standpoint it's very useful. It frees up space on my dead and I'm not afraid to spill anything. I like that it doesn't damage my desk and leaves no marks. You only have to be careful to not put something too heavy inside or it can get a little wobbly.