To do lists are useful and are out of date the instant you think of something important. Software gives you the option of quickly updating your to do list. Good software gives you options to organise tasks into projects, change priorities, and generally organise your thoughts into the best form for your use. Here are my thoughts about the applications I tried to use.
What do you get when you search for todo in the Ubuntu Software Centre? you get the list shown in the following image, featuring Zanshin, Todo list (gtodo), QToDo, Tasque, J-Pilot, SPE, and Wammu. SPE is definitely not a todo list manager.
Abiword is a very fast loading word processor with lots of options for creating lists. You can easily create a numbered list. Adding an item to the list is easy. Re-sequencing a list is difficult. Reorganising a list is too difficult. Abiword remains a good choice for documenting the details of an item in your to do list.
Bluefish is a text editor I use for application, program, and Web development. Bluefish is a fast way to type raw text. You can organise the raw text into lists but it is too manual for organising a to do list. Bluefish is more useful for creating large blocks of documentation text in programs.
Gnote is primitive. Gnote is not very good at taking simple notes. Gnote is hopeless at structuring your notes into any sort of plan. Gnote is a clone of Tomboy and uses less memory.
QToDo uses Qt for the interface and appears to be no longer maintained.
Tasque is similar to gtodo but has fewer users and is written in Mono instead of a normal programming language. Mono is an open source emulation of Microsoft's .NET and most of the Mono programs I have tested have failed. .NET is Microsoft's emulation of Java and .NET creates so many problems on Windows that I try to avoid all updates to Windows labelled .NET. Java was faulty and very slow for most of Java's life. Java is supposed to be write once for anywhere but fails both on the write once and the anywhere part. .NET is all the problems of Java plus all the difficulties added by Microsoft. Mono adds their development mistakes to those of .NET and Java. Using a Mono based application on Linux is as bad as using a KDE based application under Gnome.
Gnote is based on Tomboy. Tomboy is an older architecture and fails every time I try to use it for anything complex. Gnote is essentially the same at the user interface and uses less memory to deliver the same minimal result.
Zanshin is new, has few users, and is a monster on Linux using the Gnome interface because Zanshin is written for KDE and has to drag all the KDE overhead into Gnome. I am tired of KDE applications hogging my netbook and crashing frequently on every Linux based computer I use. I will not test Zanshin.