I just started using trello for the game I’m working on, and I’m pretty happy with it so far. It’s pretty simple, and allows you to have lists of lists. Most of the time those lists will be for maintaining what needs to be done, what you’re working on, and what is complete (sorta like a scrum board). You can have multiple boards (one for Home todo, Work, etc), and do all sorts of labeling, break out tasks, etc. It’s free to use, and I’ve been using it a lot.
It’s made by some of the people who brought you FogBugs and StackOverflow.com. You should try it out.