Not really a specific writing app, but one of the things I struggle with most in writing is remembering things I want to do over longish gaps. I have even gone so far as to start designing a tool to help me track this stuff, but it never got past the data model stage because I am rotten at designing UI.
Anyway, Hiveminder seems to do most of what I wanted to do in Juggler:
It’s not perfect, but it is also still quite new and still developing.
Thanks for the tip! I’ve had a look at Haveminder, but I’m not convinced.
In the first place, I find Haveminder too complicated. A to do-manager should be straight and simple; Haveminder clearly isn’t.
Secondly: as far as I can see, Haveminder has no alarm function; and a to do manager without an alarm for me is no to do manager.
Thirdly: the UI is ugly; but that’s personal.
Anyway, I greatly prefer the to do-feature in iCal, though I admit that this one too is not the to do-manager of my dreams.
I tried many, many to do-managers but never found one which I really liked. If I could, I would write one myself.
Have you seen the “To Do” feature in the Leopard preview? It looks very useful. Even cooler, it looks like it will be able to integrated between applications, so that you could make something from Scrivener into a “To Do” that gets listed in Mail. It looks like it will do pretty much everything I want from a To Do manager…
Seems very promising indeed! But for this handy tool we’ll have to wait until spring next year, which means it will ship only after Scrivener 2.0 … … 
Um…
[Timotheus] Fair enough. Horses for courses and all that. I must say that your impressions of Hiveminder are almost exactly the opposite of mine! Fair point on the alarm function. You can set up a daily reminder email, but that’s about the extent of it, although for me that is all I need anyway so…
Like I say, horses for courses. The winning feature for me is that it’s web based so I don’t need to have my iBook with me all the time.