Vimperator is a free browser add-on for Firefox, which makes it look and behave like the Vim text editor. It has similar key bindings, and you could call it a modal web browser, as key bindings differ according to which mode you are in.

Features vim-like key bindings, ex mode commands, hit-a-hint navigation, advanced completion of history and bookmark URLs, vim-like status bar with wget style progress bar, minimal GUI, count supported on many commands and a comprehensive help file.