One thing that annoys me in Vim is that in normal mode, the cursor defaults to being at the end of a tab character. When I hit "Home" I expect the cursor to go all the way to the left, but instead it hovers 4 spaces to the right of where I expect it to. I stumbled across the answer after reading a mailing list thread for vim.

set list lcs=tab:\ \ 
" Note the extra space after the second \

You can put this in your .vimrc to automatically set this behavior. Very useful.