If I remember to do anything these days it’s thanks to gentle, but consistent, nagging. These help with that:

Ta-da Lists

Quick management of multiple to-do lists. I have my list page sitting in an Opera sidebar so there’s an ambient level of nagging at all times. It simply does one thing really well. I approve.

Time Cave

Schedule e-mail reminders to be sent to yourself. Again, simple and I approve.

Kathleen

I approve!

Also, 37Signals‘ new creation, BackPack, combines both of these and much more (add content to a page/list by e-mail!) but it’s completely unusable to me at the moment because Opera has a few bugs in its implementation of the recently fashionable XMLHttpRequest Javascript object, which BackPack uses for just about everything. Luckily Opera gets updated all the time so I’m patient and hopeful.