This topic has come up before and I'll repeat myself. If you need a serious todo list / information manager, everything you want can be found by running emacs with org-mode.

It does everything on your list but the widget - I've thought about some ways to do this..I just don't need it personally.

It also allows tables (spreadsheets) within outlines and works very nicely with bbdb (contact manager). Due dates, repeating tasks, agenda's, priorities, todo states - all of that is easy out of the box.

I run my buisness with org-mode. Today, on a jobsite, my client requested budgets on several upcoming projects we discussed for their 2011 forecasting. I sat down with my damn phone and used several of the same spreadsheets I use on my desktop to pull 4 projects together, pasted it into an email (long live plain text!) and delivered what he needed in 30 minutes.

For my business and personal accounting, I use ledger - more plain text. My journal entries and reports are all on the phone - just like the laptop.

When I used windows, I heard about orgmode several times, checked it out, then rolled my eyes when I saw some of the jibberish required to get it running. I wanted to double click on an .exe and be done with it. A year ago, I dug in with some tutorials and never looked back. It's rather involved to setup well, but worth the pain x100.

If you look into it, don't hesitate to ask for help, I'd be more than happy to go into my setup in detail.

So, IMHO, if you call the n900's weakness the lack of a clicky todo list manager, you may be right. For me, it's ability to run emacs so well is the reason I would never consider another phone (until a successor comes along...)