Previous threads have repeatedly touched on the value of having more "at a glance" information available when scanning a list. An early suggestion of mine was the use of some icons to indicate the presence of a note or recurrence on a given task (something I still think would be helpful). C.f., http://www.rememberthemilk.com/forums/ideas/944/ and http://www.rememberthemilk.com/forums/ideas/311/

In that same thread of ideas, the desire to see tags came up recently, here http://www.rememberthemilk.com/forums/ideas/1322/, and I think it's a smart, valuable idea.

I'm not sure if anyone else has mentioned time estimate, but I can see how that'd be helpful for those who were making use of that field.

I agree with the comments re tags. I'd put it on http://www.rememberthemilk.com/forums/ideas/1322/, but it's auto-closed.

I would just like to +1 the idea of being able to view tags next to to-do items. Being able to sort a list by the first tag would also be useful, so that tasks with a certain tag would group together.

I'd like to see time estimates at a glance in the overview list.

+1 on viewing time estimates at a glance, w/o having to do a mouse over.