nicely written opinion
i have my setting set to only show the main apps running, nothing core... and every once in awhile when im not doing anything on my phone (not syncing, using pandora etc) i just do a kill all... takes me from 30-80 Mb up to about 170Mb and helps out a lot...
i dont use the autokill feature, it only takes 2 seconds max to manually do it, even faster if you have the widget...