I've been using Appigo's Todo program on the iphone with RTM. I really like the ability pick multliple Lists (folders) to show or hide in their Focus List option.
I'd love to see something like that implemented for Toodledo online and the Toodledo iphone app. And it would be great for any of the categories: folders, contexts, priorities, etc. So when I go home, I can just quickly uncheck the Work context, or the work related lists, but still see the others.