VI cheatsheet:

h,j,k,l		movement
w,b		move word-wise
0,$		move to start, end of line
^		another way to move to the start of a line
/		search
?		search backwards
%		match bracket
Ctrl+f		Move forward 1 page
Ctrl+b		Move backward 1 page
Ctrl+]		Jump to tag (e.g. in help or programming)
Ctrl+T		Return after jumping to tag
ma		Set mark a (can use any letter)
`a		Go to mark a (can be used to delete from cursor to mark)
f<char> Go to the next occurrance of <char>
t<char> Go to just before the next occurrance of <char>

i		insert
a		append after cursor (good for end of line)
A		append at end of line
r		replace with next letter
R		replace a bunch of characters
x		delete character
X		delete previous character
d<object>	cut
dd		cut line
P		paste
p		paste after cursor (weird)
y		Yank (copy)
o		open line below cursor
O		open line above cursor
u		undo
U		undo everything on current line
Ctrl+R		redo
c<object>	change object
.		repeat last delete or change command (including insertion)
~		change case and move to next character
qa		Record macro a (can use any letter)
@a		Execute macro a
>		Shift lines right
>i{		Shift inside {}
<		Shift lines left
=		Indent lines properly

!!<command>	Put the output of <command> at the cursor
!motion<cmd>	Pipe the text specified by motion through <command> and replace it with the output

v		visual mode (select characters)
V		visual mode (select lines)
Ctrl+V		visual mode (select a box)

K		Look up man page

objects:
w		word
e		word not including space
$		end of line
0		start of line

Ctrl+g		file status
G		move to line (default end)
gg		move to line (default start)

:!command	external command
:q		close window
:wq		save & close window
:w FILE		write to FILE
:r FILE		insert contents of FILE
:s/old/new/g	replace on line
:%s/old/new/g	replace in whole file
:s/old/new/gc	ask for confirmation for each replacement
:s/old/new/	replace next occurrance
:set <option>	set an option
:view <file>	open <file> read-only
:n		move to next file
:N		move to previous file
:rewind		move to first file
:last		move to last file
Ctrl+^		move to alternate file (last file being edited)
:cnext		next error
:cprev		previous error

:split		new window
Ctrl+W Ctrl+W	switch windows
:split <file>	new window with <file> in it
:3split		new window 3 lines high
:new		new empty window
Ctrl+W +	increase size of current window
Ctrl+W =	make windows the same size
:bnext		next buffer (e.g. when you have multiple files open)
:sbnext		split window and go to next buffer

Help on options: help 'option'

Good options:
set mouse=a		turn on mouse
set hlsearch		highlighting searches with /
set is			incremental search (search as you type the query)
set ic			ignore case when searching
set hidden		make buffers stick around when they disappear from the screen but you move to a new file
set shiftwidth=4	make the width of indentation when programming 4
set textwidth=0		don't break long lines
set cindent		enable C, C++, Java smart indenting
set autowrite
set autoread
map <F5> command	maps the sequence command to the F5 key
map key command		maps the sequence command to key