Hi,
As far as i know a cornerstone of GTD is lists. Today, Next Actions, Someday, ... are lists in the first place. Other types of lists also can be thought of such as shopping lists. I think without a shopping list one needs to have another app for those kind of lists. So it would be nice if the ability to add custom lists, with and without shopping list capabilities, could be added to your great app. These lists can be shown on the left list behind standard lists (Today, Next, ..., Waiting, Projects, Goals).

regards,

Parham Navabzadeh