I have had the 6600P for almost three years. It came with all teh aforementioned feet of which I use the 1/4" all the time. I have occassionally used the walking foot and it has given me no problems. It also came with the table which is in use at all times. The only thing I miss is the free arm for hems and such.
Buy the best machine you can comfortably afford. Really think about the different bells and whistles and if you will really use them. My DH wanted to recently upgrade me to the Horizon, and I said thanks but no thanks my 6600 works just fine.