Over the last month or so, I've played with a few online productivity/task list tools (Tracks, GTDTracks, Vitalist) and they all have come up a little short for me.
I've used Todoist for the last 2 weeks or so and, like Jordan Bratman, I don't think I'm going to do much better than this.
A few of the things I like about it:
Clean Interface
After hiding the info page with one click, all you see are your tasks, projects, and a minmalist search window. No clutter on the screen.
Dates/Times
Maybe the coolest feature. Tired of clicking around in Outlook, setting a deadline for something that has to be done tomorrow by noon? I'm not going to check (it takes too long), but I'd guess it takes at least 12 clicks in several different date, time, scheduling boxes. In todoist you just type "tomorrow @ 12", "friday @ 12", or even "tom @ 12". Schedule recurring tasks by putting an "every" or "ev" in front of the date. I defy you to set up a recurring task in any other system with fewer key strokes than "ev 15" (Every 15th of the month) or "ev mon" (every Monday).
Contexts
If you're practicing your GTD mantra, or just sorting things out, you can add contexts to your tasks by simply adding "@home", "@work", etc... to the task description. Unlike GTDTracks and Vitalist you can add multiple contexts to tasks you can get done either at home or in the car, or wherever.
Prioritization
Similar to adding contexts, adding priorities is simple. "!p1" makes the task a top level priority, "!p2" a second level priority, and so on. There are 4 levels, each color coded.
Keyboard Shortcuts
Along with dates, the keyboard shortcuts are what really make Todoist stand out. Adding tasks, promoting and demoting tasks and projects, sorting, and much more can be done with shortcuts.
Launchy/iGoogle/Integration
Adding the Todoist DLL to your Launchy program folder allows you to add tasks to todoist using Launchy. 'Nuf said. I haven't used the iGoogle widget yet, but I imagine it works wonderfully. A Firefox extension for g-mail lets you send e-mails directly to your task list. And so on. There are Quicksilver and Mac Dashboard plug-ins and widgets, but, like Pony Parties (definately not linking to that, look it up yourself), I won't admit to knowing anything about how they work.
Chaining
I haven't done much chaining (a la Seinfeld), but it is equally easy to implement.
Price
It's $3 per month for the premium level. That gets you SSL, reminders (MSN, Jabber, Twitter, chaining, and other labeling capabilities. You probably spend at least $3/month on plastic silverware, replacement earring backs, and contraception. Todoist is more important than any of those things. Just think how quick it will be to type "[Ctrl-A] Go to planned parenthood, take care of it [Tab] tom @ 8".
What's Missing
There is not (or I have not found) iCal or RSS functionality.
Anyways, I've enjoyed using it, sign up, get your act together, then comment and tell me how smart I am.
Now that you've used Todoist to get all your pending tasks done (or at least catalogued) and Mint to sort out your fiscal world, it's time to sit back and relax. 
