Four free programs:
I use
Wunderlist for tasks. I use it like I would a sheet of paper, just writing down reminders of dozens of little jobs and tasks I'd otherwise forget.
For breaking down ongoing projects into component tasks (Eg. building out a site), I tend to use mind-mapping software rather than to-do lists, and recently I've started using Gantt charts to try to make sure I stay on target over several weeks/months. I like
Xmind for mind mapping, but if you don't mind cracked then ConceptDraw is hard to beat.
For my daily schedule, I'm trying
Interactive Calendar It has a to-do list interface, but the output is to a calendar which is embedded into your desktop. The problem with Outlook's calendar and tasklist was that I never looked at it enough. This way, my list of tasks for the day is hard to ignore, because it's my wallpaper.
Finally, for timing/tracking today's tasks, I use
WatchMe. It's not the nicest looking clock, but it's great for listing all your tasks for the day and timing them all, a little like 'action machine' mentioned above.