The key to staying on track with the stuff you need to get done is to write it down and systematically check it off-whether you do so online, on your desktop, on your smart phone, or in a plain-text file. PC World has tried various online task managers, and Remember The Milk is our favorite. It provides all of the features you'll ever need in a to-do list online, on your desktop, and . on your phone. RTM: offers task categories (such as Work and Home), file attachments, notes, priori¬ties, tags, due dates, and even "honey do" items (you can send tasks to other RTM users, such as your spouse or assistant). RTM also has a Firefox extension that integrates the service with your Gmail inbox, so you can turn e-mail messages into tasks. Of course, no matter how good your software is, nothing can replace the visceral satisfaction of crossing off a line on your paper to-do list with the stroke of a regular old ballpoint pen.