I really want to recommend on OmniOutliner which is a mixture of a notes application with some tree-based items, bullets and even "Excel-like" structured table with drop down lists, checkboxes, etc.
I'm using it on a daily basis for summarizing meetings in a structured list of items with hierarchy and status columns, I'm managing my personal todo list inside of a page, I'm writing my ideas and roadmap items (I'm a product manager) in a separate page - I love it.
Best feature: being able to create great looking tables, manage them, and then save as html...
After trying Notes, Pages, Todo lists, Things, EverNote, QuickOffice or anything else that can be used as a free notes app, tasks and more - my recommendation is to try OmniOutliner:
OmniOutliner – the best productivity app for iPad
Only missing feature for me is a decent sync with my laptop (not mac... so there is no native version for it...) - if anyone knows about a workaround I will be happy to hear.