Inspired by the Lifehacker Pack, I created my own list of tools I use on a daily basis. I've listed Linux alternatives to the Windows-only tools, but I haven't used a Mac since grade school and I didn't want to blindly recommend anything.
- Google Chrome - Web browser available on most desktop and smart phone platforms. Allows bookmark, extension, and open tab syncing between devices and a wide range of extensions. You can also enable Google Instant in the address bar from the Settings menu. It's called Chromium in Linux. But if you're using Linux you already knew that.
- Launchy - Instead of going the Start menu to launch applications, you just press Alt-Space and begin typing the name of the app. Supports plugins as well. Linux alternative: GNOME Do.
- Picasa - Photo editor from Google that syncs nicely with Google+. Plug-ins for social networks that people actually visit exist too.
- Ditto - Clipboard manager that saves the last 500 items you've copied (don't worry, they're searchable). Now you can copy multiple sections of text and paste them individually with a single hot-key press. Linux alternative: Parcellite.
- Sublime Text - Beautiful, cross-platform text editor that is 1000x more powerful than Notepad. Windows-only alternative is Notepad++.
- 7-Zip - Open source Winzip alternative that supports many more file formats.
- Snipping Tool - Great utility that comes with Windows 7 that allows you to capture a screenshot of any portion of the screen you want.
- Sumatra PDF - Lightweight Adobe Reader replacement that's much faster.
- CCleaner - Utility that deletes temporary files and fixes registry issues to speed up your computer (and it's not one of those scam programs as seen on TV).
- WinMerge - Quickly compare two versions of a text file to see which lines differ and merge changes between them.
- Rescue Time - Track which window or website has focus so you can see where you're spending (or wasting) your time.
- Clover - Tabbed Windows Explorer interface modeled after Google Chrome. It even has a lot of the same shortcuts. Windows only.
If you have other great Windows, Linux, or Mac tools, leave a comment below.