And, per our requirement, your Re:snooze items are all available online from any Internet-connected PC.

Evernote

The combination of reQall and Re:snooze covers individual tasks -- both one-off and recurring -- brilliantly. But these two services aren't great for organizing whole projects, which GTD defines as anything that requires more than one action. So, for example, "Take a trip to Italy" is a project. "Buy tickets" is an individual task within that project.

Those two applications handle text, but can't deal with a wide range of other forms (although reQall, surprisingly, has a photo section). That's where Evernote comes in. Evernote lets you drop just about anything -- text, Web pages, photos and other things -- which are then indexed and made searchable.

Here's just one example of the magic that Evernote can perform. Let's say your travel agent mails you a paper-based itinerary for your trip to Italy. Just use your PC's video camera, your cell phone, your digital camera or your scanner to take a picture of that paper. Drop it into Evernote, and the service will recognize the text in that picture, index it and make it searchable just like text you type in.