VIM

Copy, cut and paste

v to select characters (V to select whole lines).
d to cut (or y to copy).
P to paste before the cursor, or p to paste after.

Search and replace

:%s/foo/bar/g

.vimrc

set wildmenu
set wildmode=longest:full,full

Moving

C-o jump to previous location

Buffers

:bn next buffer

Scroll

^F ^B scroll page up, down

To comment out blocks in vim:

hit ctrl+v (visual block mode)
use the down arrow keys to select the lines you want (it won't highlight everything)
Shift+i (capital I)
insert the text you want, i.e. '% '
Press ESC