The GUI browsers
Mozilla Firefox gained more and more popularity since its initial release in November 2004, and today is the browser of choice for the majority of Linux users. Although relatively new compared to other browsers which date for over 10 years, Firefox became a myth in the web browsers world, not only on Linux, but on Windows too. It uses the open-source Gecko rendering engine, it's well-known for being very secure, it manages passwords and cookies very well, it can be expanded by using various add-ons, it supports themes, and those are just a few of its features. The new release, 3.0, also brought several usability improvements, like a new location bar, which makes it easy and fast to find the address you are looking for. It's also highly configurable, and the options which are not available in the Preferences window can be set using the about:config command in the location bar. In my opinion, its only minus is that it takes a considerable amount of time to load, it occupies a lot of memory, and the interface is a little bit slow. Otherwise, probably the best browser available on the Linux platform.
Built using the Qt toolkit, Opera is closed-source, but it compensates introducing many features, like a BitTorrent and IRC clients, tabs for most of the actions available (like the transfer window), widgets, plenty configuration options, a cool default interface (the black one in Opera 9.50 and 9.51 really looks awesome if you ask me), system tray integration. And those are just some of the highlights. Opera probably offers the most usable graphical browser to date, and it's definitely a feature-complete browser.
Using the KHTML engine for displaying web pages, Konqueror is the well-known browser (and not only) for KDE. Although not as powerful at displaying pages as Firefox, Konqueror uses less resources, it has very good KDE integration, allows previewing of audio, video and image files, it integrates well with KGet, a powerful download manager, it supports plugins, it offers spell-checking, and it's highly configurable. For KDE users, Konqueror should be the right choice.
Epiphany is the default web browser in GNOME, built in GTK and using the Gecko layout engine. Epiphany has a simple and clean interface, it doesn't look bloated, and it can take advantage of plugins. Some say it uses less resources than Firefox, although I wouldn't bet on it, the difference to me doesn't look significant. Nevertheless, Epiphany is a good alternative to Firefox, especially that it integrates very well with the GNOME environment.
The first time I bumped into Dillo was when I tested a version of Damn Small Linux from the 3.x series. I remember I didn't like it at the beginning because it just didn't look to provide the features I needed. But since it's so small, Dillo is actually a great little graphical browser which is worth a try.
Yet another GTK application, Galeon is pretty powerful and includes all the important features you would expect from a web browser.
An interesting browser, Kazehakase can use the Gecko engine, it supports mouse gestures, it allows three different levels for interface, Beginner, Medium and Expert (called UI Levels, depending on which one is selected the interface offers less or more options and menus). Kazehakase also supports tabs, and allows you to modify its interface by editing the /etc/kazehakase/kz-ui-UI_LEVEL.xml files, where UI_LEVEL is either beginner, medium or expert.
The CLI browsers
lynx is one of the well-known and full-featured web browsers for command line.
Another CLI web browser, links has mouse support.
w3m is another popular and powerful browser for command line with support for tables and frames.
elinks is a fork of the links web browser, running only in text mode, with mouse support.
Similar to lynx, this web browser supports background downloads, and can be run in graphical mode using the links2 -g command.
Updated: Jul 16, 2008 (Created: Jul 16, 2008)