Firefox is probably the most powerful web browser. It has been around for about ten years and ships with changes and features with each new release. Firefox has support for add-ons with hundreds available for download (for both users and web developers), themes, personas, history, privacy, bookmarks and what not.

Chrome is the well-known and very popular browser backed up by Google, using the Blink engine. It is full-featured, and it is the only one that bundles an updated version of Adobe Flash Player (since further development for the plugin has been abandoned by Adobe, except for security updates). Just like Firefox, Chrome comes with all the features one could ask from a web browser, and its functionality can be extended via add-ons.

Developed by a Norwegian company, Opera is a popular and very powerful web browser, using the Blink engine, a fork of WebKit. Although closed-source, it is prefered by some users because of its unique approach, a clean, organized interface, and very good web page loading speed. Opera hasn't seen a new version on Linux in a while, but the latest stable release is full-featured anyway and does its job very well.

Formerly known as Epiphany and based on WebKit, Web is the GNOME browser. It is a bit simpler when it comes to features, but it bundles enough to make it a very good, usable on a day-to-day basis browser. Web has a very clean and simple interface, somewhat similar to the one of Chrome, support for tabs, bookmarks, privacy settings and plugins. It uses the WebKit engine.

Chromium is the browser on which Google Chrome is based. Just as Opera and Chrome, it uses the Blink engine.

QupZilla is a wonderful web browser using WebKit and written in Qt4, making it perfect for KDE users. It has pretty much the same interface and features of the earlier versions of Firefox, with the classic interface.

Pale Moon is a fork of Firefox, retaining its features and power, and also its older, classy interface. It uses the Gecko engine. Unfortunately the latest release (24.7.2) seems very unstable on Ubuntu 14.04.

Dillo is a minimalist web browser with the goal of staying small and not be resource-hungry. Dillo has support for tabs, and understands HTML/CSS, but has no support for JavaScript or videos. Dillo is just great for testing simple CSS or reading HTML-only documents without the need to fire up a heavier application.

Although not yet available for Linux, according to the homepage the Ubuntu version is almost ready.