I have a Brown Headed parrot (Poicephalus) and many of the sites I researched mentioned that they were good appartment birds, because they are really not noisy. Here' s my opinion after a little over a month with mine.
Noise level : very low, makes really soft sounds, maybe one loud scream per day (lasts 20-30 seconds)
Activity level : medium
Cuddleness (sp?) : high (loves to be petted everywhere, kissed, grabbed, name it). Wants to be with you all the time
My conclusion : definitely a very very good parrot for appartment living conditions !