While there is a number of GUI versions of vim (gVim, MacVim), I personally use the console version. The main reason for that is that I often ssh to remote servers (including my office computer when at home) – and use vim on-the-spot.

Customizability is what makes vim much more than just a text editor.
Customizing vim includes:

1. Grabbing a nice color scheme
2. Getting some plugins that would simplify your everyday work
3. Binding of commonly used keys
4. Realizing your desired functionality in vimscript

My preferred color scheme is IR_Black. In order to be able to use it in Terminal vim, you will also need the corresponding Terminal color scheme. Todd Werth describes the installation process.
While the TextMate users are enjoying the beautiful color schemes, vim people are porting them. Among the ports are the Zenburn color scheme, VibrantInk and Twilight.

If you are a fan of pixel fonts, Terminus is a good font that is both crisp and easy on eyes. If you are not, then may be the excellent Monaco font is your friend.

The plugins that are featured in the screenshot include NERD Tree and MiniBufExplorer. The others that I also use and recommend are NERD Commenter and vim-git-branch-info.

Vim.org includes thousands of plugins, including a great Rails plugin, project plugin, code browser and much more.

Damian Conway has recently published a tutorial on vimscript on the IBM developerWorks portal, so check it out if you want to become a power user of vim (Part 1, Part 2).

Bram Moolenar, vim author, has made a speech concerning effective text editing with vim.

If you are new to vim, feel free to check out my .vimrc on github and modify it to your needs.