Great To Do List - I have been using it for year. I particularly like the fact that it has a PocketPC version as well that you can add for another $10 making a total of $14.95.
But if you don't use a PocketPC, you just pay $4.95 for the next few hours.
The Ultimate in Lists
ListPro - save 75%
Regular price: $19.95
Bits du Jour Today Only price: $4.95
You save: [Huge Discount!] 75% [Huge Discount!]
You don't have to be compulsive to like lists.
Lists are great. They're interesting - there's a reason why so many sites and TV stations have lists. But more than that, they're useful.
Lists of things to do. Packing lists. Holiday gifts. Groceries and other shopping. Books, CDs, DVDs. Event planning. Beanie babies. Timezones. Restaurants. And almost everything else.