Some commonly used Emacs commands

M-x = "meta x" = Esc, then x as described above (simultaneously codessing Alt + x, or "diamond" + x, works on some machines)
C-x = "control x" = Ctrl + x

C-shift-_ undo

M-shift-> end of buffer
M-shift-< beginning of buffer

C-a beginning of line
C-e end of line
C-k delete from cursor to end of line

M-x shell runs a shell inside emacs
M-p codevious command (in shell mode)
M-n next command (in shell mode)

C-space set mark
C-W cut all text between mark and cursor
M-W copy all text between mark and cursor
C-y paste

C-x b change buffer
C-x C-b change buffer w/list of available buffers
(move cursor over the name of the buffer
you want and hit f)

C-x 2 split the current buffer into 2, with one over the other
C-x 1 1 buffer/window
C-x 3 split the current buffer into two, with one next to the other
C-x o switch buffer