I reviewed an app back in January 2010 (http://www.iphonelife.com/blog/3963/awesome-note) called Awesome Note.
I still love the app. I use it everyday and have recommended it to many of my friends and family.
They have recently added some really cool features. I'm going to include all the screen shots from their website for those of you who are not familiar with it. It's easier to see it, than explain it.
Awesome Note is not just a to do list, it's also a journal, assignment book, reminder and organizer. This is a great tool for Moms, Dads, Students (Middle, High & College), Business Executives, Assistants, Teachers, Publishers who think they are uncool - but are really so cool that they come off as uncool......basically, it's an app for anyone.
The awesome thing about Awesome Note is that it syncs to Evernote or Google Docs. I have the app on my iPhone and iPad. As long as I remember to hit the sync button, they are always in sync. They haven't updated the app to take full advantage of the iPad's larger screen, but I'm sure it's in the works.
There is a passcode for the whole app or just certain folders. A great way to keep prying eyes out of your gift list folder.
This is the best all around list/note app that I have found. It is worth $3.99. It's actually worth a lot more (but don't tell the developer that!!).
Go to: http://bridworks.com/anote/en/main/ to purchase or see more details.
Remember to sync!!!