A while ago Mashable had a list of 230+ keyboard shortcuts for popular web services, now Smashing Magazine has 200+ more to increase your productivity, enhance your time-management and improve both your professional skills and the quality of your work.

Some Firefox keyboard shortcuts

From the article:

This post covers the most useful keyboard shortcuts for essential software applications users and web-developers can/should use on a daily basis - OS, Browsers, Music Players, Communication Tools, File Management and Coding. You will also find references to related resources - there you’ll find more specific shortcuts for your needs.

The list includes popular software titles such as Winamp, Total Commander and Microsoft Outlook.