I think it's a matter of personal preference as to the program you use. I would suggest downloading a trial of PSP and PSE to compare with your PS & go from there. I'm not familiar with the other programs designed specifically for scrapbooking, but from what I've heard they are limited in function.
Personally, I prefer to do my layouts in PSP and/or PSE. I do my design work mostly in PS7, although I do some things in PSP.
"The greatest treasures are those invisible to the eye but found by the heart." Author Unknown