Here is a non-exhausive list of really great vim plugin:

pathogen

For plugin management, after installing you can keep all your plugin in a ~/.vim/bundle. You can keep every plugin as a git depot for git-submodule management or similar. http://www.vim.org/scripts/script.php?script_id=2332

conque

A shell wrapper you can open a shell in a vim buffer simply with

ConqueTerm ipython

or

ConqueTerm zsh

http://code.google.com/p/conque/

ack

A simple shortcut to the ack command, a grep alternative specially designed for programmers. To search for all the source code for a word with some grep option by default. https://github.com/mileszs/ack.vim

surround

add or remove surrounding, it support parenthesis opening and closing. For example:

"hello" to 'hello' with cs"'

https://github.com/tpope/vim-surround

The-NERD-Tree

A file browser in vim, much better than the default one. https://github.com/scrooloose/nerdtree

auto-mkdir

Automatically create the directory that doesn't exist yet when editing a new file.

minibufexplorer

always see all opened buffer, change between them, see wich one are selected. https://github.com/fholgado/minibufexpl.vim

snipmate

Very good snipet utility, very easily scriptable.

superTab

tab make the completion for everything, snipet completion too if you have snipmate

vim-powerline

status-bar on cocaine, with svn, git status, encoding, end of line, and more

speedating

Increment/Decrement date with ctrl+a/ctrl+x, works so well you will loose your calendar. Very handy to build macro on top of it.

ZoomWin

Maximize one window, then go back to the original layout

jslint

a simple linter with the quick fix window support

css-color

add the color of every color tag as the background for example: html { color: blue } the background of blue will be blue

Pydoc

Works very well for the default cpython lib. will open a new buffer in a new window with the corresponding doc when completing.

Rope

Renaming at project scope, changing element and moving code around. Works really great

Pyflake

A simple linter with quick fix window support

Vimerl

The best plugin around for programming in erlang with vim https://github.com/oscarh/vimerl