Really interesting. I’ve been using evernote just to reference things and use toodledo free account to do the main GTD task managment. That’s synced with my ipod touch(by Appigo ToDo app) and nexus one (by Got to do). I have just stumbled upon Springpad and that is very promising. I think I’ll stick with Toodledo as you can tag a status (e.g. Next Action) and a category which I don’t think you can do in Evernote easily.