Sometimes, it's easiest to cheat

When it comes to learning Vi, anyway. . .

When I was trying to get my head round it, I went through vimtutor and made notes of the interesting & useful commands. The most useful ones, I saved. And here they are, for whoever wants them:

(The formatting doesn't preserve wonderfully, I'm afraid)

===============================================================================
                       VIM cheat sheet
===============================================================================

h, j, k, l     -       left, down, up, right
)              -       Beginning of next sentence
(              -       Beginning of current sentence
$              -       end of line
^              -       start of line

CTRL-E         -       Scroll down a line
CTRL-Y         -       Scroll up a line
CTRL-F         -       Page down
CTRL-B         -       Page up
CTRL-D         -       1/2 page down
CTRL-U         -       1/2 page up
CTRL-G         -       Show position
n Shift-G      -       Move to line n

/text          -       Search for text
n              -       Search for next instance of text
:set ic        -       ignore case
:set noic      -       stop ignoring case
%              -       Find matching ) > ] etc
:s/old/new     -       Change the next occurence of old to new
:%s/old/new/g  -       Replace all old with new
:n,ns/old/new/g        -       Replace all old with new from lines n to n

u              -       undo last commands
U              -       undo whole line
CTRL-R         -       undo the undo

r              -       replace current character
R              -       Overwrite text
x              -       delete current character

d              -       delete things
    dw        -       delete word
    dnw       -       delete n words
    de        -       delete word but not space
    d$        -       delete to end of line
    dd        -       delete line
    dnd       -       delete n lines

p              -       put

i              -       insert text
o              -       Open line and enter insert mode
a              -       append text
A              -       append to end of line
:!command      -       execute external command
:r filename    -       read filename into current file

:w (name)      -       write (to file name)
:n,n w (name)  -       write lines n to n (to file name)
:q!            -       quit without prompting

mx             -       mark current position as x
`x             -       move to mark x
'x             -       Move to start of line containing mark x
:marks         -       list current marks

guw            -       Change current word to lower case
gUw            -       Change current word to upper case

yw             -       yank current word
v              -       visual mode (select)

I hope that helps any prospective Vi users. If not, run through vimtutor and make your own :P