Put Check Off on your download to-do list
If you simply must tweak, then Check Off lets you do that too. Create folders for each area of your life -- work, home, kids, hobby, etc. -- and nest to-dos inside each one. You can color code each folder, name it anything you like, and display notes in global folders or inside each task. As an added bonus, Check Off lists can also be downloaded to iPods that support the notes feature.
Check Off may not be the most full-featured to-do list manager out there, but it's simplicity and usefulness is what makes it so attractive.