Task Tools

Replace your audience response systems with Poll Everywhere

http://todoist.com/
Web-based. mobile (dozens of phones), and iPhone app (called mintTODO)
Simplicity in design and ease of use; nice hierarchy
Create categories, and subcategories, expand/collapse them
Use @ for labels and query search these labels easily
Reorder lists easily and lots of shortcuts too
Add * before a task to make a note and not a checkbox/date
Gmail integration, iGoogle Widget, firefox toolbar, other APIs to integrate w/ other aps
Uses Ajax for quickness, but required Javascript
Only $3/month to upgrade to Premium Service which included reminders, twitter, and other options
Similar to Things for Mac

http://www.rememberthemilk.com
Web-based, iPhone/iPod, Droid, Blackberry, and mobile browser access (pro version $25/yr for use with some mobile)
Create tasks, task actions, due dates, prioritize, tag, time estimate, add url, notes, share...
Organizes tasks by category , by priority, by date, by tags ...
Search and then save that search as a Smart List
reminders! through email, SMS, IM, twitter
Integrates with gmail, googlemaps, google gears, igoogle gadget, Twitter, firefox extension, RSS feeds...
Lots of API integration (details)
They have a monkey named Bob.
To find a list of overdue items type "dueBefore:today"
Using Time Estimate tips
here is a list of shortcuts/smart adds

Vitalist

Things