People often refered to emacs as being an awesome operating system, that thoroughly lacks a decent editor. I used to agree, because I vastly prefer modal editing as pioneered by vi and its various clones. But no more! While there have been multiple vi emulation modes for emacs (VIP and Viper for example; also vimpulse and vim-mode for a few of vim's more prominent features), none of them sat exactly comfortable with me. Then a few talented elisp hackers got together and wrote evil, the extensible vi layer for emacs.
Earlier today, Frank Fischer announced the release of version 1.0.0 of evil, which marks the first stable release of the software. I've been using evil for quite a while now and it is by far the single best piece of software to get modal editing into your emacs. Do check it out and let the developers know about any problems you encounter!