Stolen shamelessly from this site.
map <c -J> </c><c -W>j</c><c -W>_ map </c><c -K> </c><c -W>k</c><c -W>_ set wmh=0 </c>
The first two lines allow you to switch between splits much more smoothly — just press
The last line allows splits to reduce their size to a single line (which includes the filename and position); this saves a lot of space when you have many splits open. By default, vim forces splits to include an additional line that contains the line of text the cursor was on in that file.
This gives you some sort of stacking functionality like in wmii