Workflowy - A better way to organize your mind.
BucketList.net - Bucket list ideas, advice and support
Dynalist - Dynalist is a web app that lets you break down and organize your thoughts in the format of lists.
Life Listr - ***AS FEATURED BY APPLE***
SuperNotecard - Introducing SuperNotecard. SuperNotecard is an online writing tool that features virtual notecards to help arrange facts or scenes, track details, organize paragraphs, and clarify your composition process.
Bucketlist.org - Log and catalog all the stuff you want to accomplish before you expire.