Browsers
What browser is best? It's a trick question. Even on Linux you must use at least two to get the job done. Aside from the bloat, Mozilla 1.3 - 1.4 is the best for most sites* and it's engine is the base for other browsers like Firebird and Dillo. These last 2 use efficient coding and provide a minimal interface. Konqueror is the KDE browser and, similar to Internet Explorer, it is used for browsing your file system as well as web browsing. It can do easily what Mozilla can not. One of those actions is provide browser header info to spoof a specific browser such as IE 6.0. As MS (M. Stewart would say, this is a good thing. You can do this in Mozilla, but it's a tedious process to accomplish - unless you are a script junky - Mozilla can be scripted extensively. As for proprietary browsers, I can safely say I have never tried any on Linux, but I hear tell Opera is the better in this class.
*Speaking of Proprietary
These little jewels do make or break a sites functionality.
Sun Java JRE
When downloading this, make sure to get the version compatible to your system (if this is still an option).
Macromedia Flash
Increasingly, sites are using Flash to make buttons, animations and navigational interfaces. Macromedia owns this baby and keeps making it better. Macromedia has a web site editor called Dreamweaver MX, which tops them all in the Windows world. It includes Flash MX and one can easily get hooked into making fancy buttons with it. The problem you might ask? It runs only on Windows systems and there are lots of poor souls out there who are unable to install much less download flash plugins.
Gimp
Gimp is a GPL image editor, which ranks right up there with Corel Photopaint or Adobe PhotoShop. Imaging Coolness example: I made a new blank 1024x768 image, opened the pattern fill, tweaked a slider, applied cubism filter and WOW! What a wallpaper! Soooo cool. Gimp can perform wonderous photo manipulation as well, perhaps even better thanks mostly to the extensive scripts through script-fu. One thing to keep in mind with Gimp - use Layers - also true for proprietary image software.