I use both regular and organic. I go by the 'dirtiest list' and use organic for all of them plus all the greens except for broccoli which is safe to feed 'regular' so, in my gloop, all the grains and flax seed, the peas and carrots and the blue curly kale are organic while the beans, corn, broccoli, sweet potatoes, green beans and artichoke are not.
When in doubt, go to the 'dirtiest list' (I also buy all the leafy greens organic). You find it here:
http://www.ewg.org/foodnews/dirty_dozen_list.php