I found Awesome Note recommended at Evernote. It works with the iPad and the iPhone.
When I need to scribble a phone number someone is tossing in a tearing hurry, I tap on the quick memo icon. Journaling is easy using the diary interface and you can add pictures which take neatly the exact width available when opened on either device, or as icons. Every kind of list can be created, for shopping, packing, reading, anything. The to-do list gets so pretty it beckons you to it, and you go without hesitation, and thereafter all you need to do is do the to-do! Notes can be grouped into folders, and folders can be stacked, and stacks can be arranged for easy reach.
Using the app is easier than it reads here.
The app syncs with Evernote and
Dropbox (sorry: Google-Docs), and I use Google-Docs. Note taking on both the iPad and the iPhone is a pleasure with Awesome Note, thanks to the soothing interfaces, but I am surprised BRID haven't a Mac version with which the iPAd and iPhone versions sync, and complete a Mac-life. I hope they are working on it, and I wish that many are buying what is now on offer, because this is an app for which I am praying for everlasting life.
For the full range of planning and comprehensive task management with a GTD approach I go to Omnifocus, but for use as a digital notebook for journaling and notes and lists and for simple today's to-do, Awesome Note has been a terrific find.