Office Applications
Office applications are ubiquitous in computing. You'll almost always need at least a decent word processor and sometimes even a whole suite of office applications. Here's a collection of free office applications that are highly regarded.
OpenOffice.org is the open source office suite that came about as a spin-off of Sun Microsystem's Star Office (which is a paid office suite). OpenOffice.org aims to be the main competitor to Microsoft Office and it compete reasonably well. The suite includes a word processor, spreadsheet, presentation software, database, and drawing application. The word processor, Write, is the strongest application of the suite, although the rest are very capable replacement for Microsoft Office if your demands aren't too great. The spreadsheet app does not include support for Excel macros and many other features that die hard Excel users would require but should serve you well if you don't do any of that stuff. Likewise for the database app. Impress, the presentation app, is a capable replacement for PowerPoint. OpenOffice.org can save files in its own open source ODT format or a variety of proprietary formats such as DOC, PPT, XLS, etc.
PortableApps.com has packaged OpenOffice.org into a portable app so you can run everything from one folder. The only difference is that the portable version is a little bit behind the official release. But if you need to take your office suite with you or just want to try it out without installing anything on your system, the portable version is the way to go. Both versions are available for download here.
AbiWord is a free word processing programs available for Windows, Mac, and Linux, although only the Windows downloads are provided here. If you need the other versions, you'll need to visit the developer's site. AbiWord is part of the GNU Free Software Collection and is able to handle a varietyof everyday word processing tasks. The user interface is very similar to Microsoft Word and is quite elegant. AbiWord will read a variety of industry standard document types such as Microsoft Word, OpenOffice.org documents, WordPerfect documents, Rich Text, HTML, and more. Although definitely not as feature rich as OpenOffice.org's Write or Microsoft Word, AbiWord is more than capable as your everyday word processor.
You can run AbiWord as an installed program from the setup file above or as a Portable App. A portable app runs everything from 1 folder, making it easy to take with you on a USB drive or to test drive a new piece of software. Uninstalling is just a matter of deleting the entire application folder, leaving nothing behind.
Sunbird is a very nice, open source, calendar program from Mozilla. It will help you organize all of your appointments, tasks, etc. from a very elegant user interface. You can set up reminders for any event and also set up recurring events based on a number of rules, such as birthdays and anniversaries. Sunbird strives to be the best at what it does and does not include extras that you may find on other PIM's because Sunbird is only meant to be a calendaring program, not a contacts manager or anything else. It does succeed quite well in what it was designed to do. I use Sunbird everyday and would highly recommend it.
Mozilla Sunbird is also available as a Portable App from PortableApps.com. A portable app runs everything from 1 folder, making it easy to take with you on a USB drive or to test drive a new piece of software. Uninstalling is just a matter of deleting the entire application folder, leaving nothing behind.
Lightning Extension is very similar to Mozilla Sunbird, except that it runs as an extension to Thunderbird, Mozilla's email client. Based off of the same code base as Sunbird, Lightning offers the same features but with some new ones in development that will make it a favorite for Thunderbird users, such as email-to-task linkage, address book integration, etc. For now, it offers features similar to Sunbird. To install, download the extension file and install via Thunderbird's Tools/Add-ons menu (Thunderbird 2) or Tools/Extensions menu (Thunderbird 1.5).
Sumatra is a very minimalistic PDF viewer. The user interface does not have a lot of options or controls and for this reason, some people may favor it over other PDF viewer. It's small and very fast to launch. It has very few compatibility issues opening all types of PDF's and by default is portable. Just download, unzip to 1 folder and run the app.
If you need to create PDF's, PrimoPDF is the application for you! Completely free, it allows you to create PDF's from virtually any Windows application by printing to PrimoPDF from that application. You can choose to set up several PDF creation profile for printing, screen use or whatever and create really quality PDF's for free. PrimoPDF does not have the bells and whistles of Acrobat, but that's not what it's trying to do. It simply allows you to create PDF's for free. A great piece of software.
Foxit Reader is a great PDF viewer that's free for personal use. If you want to create PDF's you'll have to buy the Pro version, but for viewing, printing and other general work with PDF's, Foxit Reader is great. The whole application is in one executable for the ultimate portability. It works great and I use it all the time.