Along the same lines, I use the following in my .vimrc
to let me move through the splits, automatically expanding the one I'm moving to to its full size and shrinking all the rest to their minimum height or width:
" Switch between window splits using big J or K and expand the split to its
" full size.
"
" Move vertically in the window through the horizontal splits...
map <C-J> <C-w>j<C-w>_
map <C-K> <C-w>k<C-w>_
" Move horizontally in the window through the vertical splits...
map <C-H> <C-w>h<C-w>\|
map <C-L> <C-w>l<C-w>\|