I would find it immensely useful to be able to see the task's tags directly in the task list (e.g. in the Next list, project list, Today list etc).

Why?

1) When I select which tasks to do it helps me quickly locate specific types of tasks directly in the list, without having to filter the list.

2) In some cases, filtering can be impossible (even with advanced search), but even when quick filtering by tag is possible it is so much quicker to just look, especially if the list is short.

3) When reviewing the lists, it is also easier and quicker to verify that each task has the right tags applied, so that I do not have to open each task and look.