Note: in emacs terminology, "META" may refer to either "ESC" (which I tend to use), or some combination of ALT/CTRL/??? keys — if you do most of your typing on one keyboard, it may be worth figuring out which combination works for "META". 


Editing, files, and exiting emacs
Default Keystroke(s)         Meaning
^X^C Save and quit
^X^S, ^Xs Write file, write all files
^X^W somefile Write to a new file somefile
^X^F somefile, ^X^V Start editing a new file called somefile
ESC X revert-buffer Start editing over, forgetting all changes since last save


Manipulating emacs windows
Default Keystroke(s)         Meaning
^X2, ^X3 Split windows
^Xo Switch windows
^X^ Make a window larger vertically
^Xb Switch the current window's buffer


Default Keystroke(s)         Meaning
^F, ^B, ^N, ^P The big four: left, down, up, right (←, ↓, ↑, →)
ESC F, ESC B Forward one word, back one word
^A, ^E Beginning of current line, end of current line
^V, ESC V Forward one screen, back one screen
^Ssomething Incremental search forward for something
ESC x isearch-forward-regexpregexp Incrementally search forward for regexp (very powerful!)
^Rsomething Incrementally reverse search for something
ESC > Go to last line
ESC < Go to first line
^SPACE Set mark (start creating a region)
^X^X Go to mark


Default Keystroke(s)         Meaning
^X( Start learning a macro
^X) End learning a macro
^Xe Execute a macro


Default Keystroke(s)         Meaning
^K "Kill" from this point up to the end of line (saved in "kill" ring)
^O "Open" a new line immediately below current, "open" a new line immediately above current
^T "Transpose" the current character and the next one
^W Cut the current region (saved in "kill" ring)
ESC W Copy the current region (saved in "kill" ring)
^Y Paste from latest item in "kill" ring
ESC x query-replace something RET otherthing Replace something with otherthing
ESC x query-replace-regexp regexp RET otherthing Replace regexp with otherthing (powerful!)
^Y Paste from latest item in "kill" ring
ESC x undo Undo