Bar none, the one thing that people do most with their computers is live on-line. Web browsing, social networking, instant messaging and e-mail are the most vital ways the postmodern Webizen stays in touch with the rest of the world. We've already touched on e-mail. The other non-browser-centric way people keep in contact is via instant messaging. There are a number of IM clients on Linux; some of them are protocol-specific (such as Amsn, which also supports audio/video conferencing for the Microsoft Messenger Network), and some of them are universal. The best of breed for the universally compatible ones is Pidgin.
Once known as Gaim, but forced to change its name due to a trademark dispute, Pidgin is a multiprotocol instant-messenger client with tabbed message windows and an impressive array of plugins, including support for two very powerful encryption schemes to keep conversations private. The interface is simple, the program is easy to use, and it doesn't get in the way—all must-haves in an IM program. Pidgin doesn't support audio or video chat (few clients for Linux do), but all the other great peer-to-peer conference features to which users are accustomed are readily available.
Of course, when talking about Internet software, one must discuss the granddaddy of all Net software, the Web browser. Although there are a lot of viable options for simple Web browsing, if you're looking for something that will give you tabbed browsing and RSS feeds, support Flash videos and games, let you watch audio and video in embedded Flash and JVM players, and give you good, intuitive privacy management with a reasonable level of security, there is only one choice, Mozilla Firefox.
A few years back, this wouldn't have been a relevant category, but between the ubiquity of digital cameras and the glut of presentation software, everybody needs a graphics package—two of them, actually: one to organize the photos (otherwise, how are you going to find that perfect shot among the thousands you rattle off each year?) and the other to edit them.
Organizing photos is a tricky job, though it's one that people are a lot more familiar with in these days of Flickr than they were ten years ago, when the shoebox at the back of the closet overflowed with pictures to sort and put in albums...someday. In the Mac world, everyone uses iPhoto. It's ubiquitous, it makes slideshows, and it does rudimentary adjustments in the program. On Windows, there's Picasa, which is focused more on printing than indexing. On Linux, there's F-Spot and digiKam. F-Spot is a rudimentary, but user-friendly, indexing system. digiKam, on the other hand, is far more sophisticated, with integrated color management, gallery creation, iPod interface, slideshow and calendar creation, and RAW format handling, all underneath a well-laid-out interface. In this game, it's the clear winner.
For graphics editing, there isn't such a clear winner. The field is dominated by two very robust contenders: Krita and The GIMP. I published an in-depth article in the July 2007 issue of LJ reviewing Krita and its advantages over The GIMP. The philosophies of the two programs are very different, as are the interfaces. The GIMP has a broader user base at the moment and more available plugins, and Krita offers more professional color management and a broader array of basic editing tools. Currently, they're very different programs, and from the point of view of the lay user, a lot is going to boil down to personal taste in interface. Either will serve very well.