At Campingworld (available retail or catalog), I purchased and
installed some battery powered (2, A-cell) lights, which are
"touch" sensitive.  They are located so that they go ON when
the cabinet door opens, making it a lot easier to see inside
the shelves.  The interior above the sink light does a good
job of illuminating the general space, but I always had to
grab a flashlight if I wanted to view the cabinet contents
in anything but broad daylight.  I got this idea from
something Bob Hoover told me about having DC wired his camper.  This
was a lot easier of an installation for me!  Anyway, the things are
about $6 a piece, and I'm pleased with the result.  They attach
with magic-mounting sticky foam tape (which comes with the product).
They also are packaged with batteries complete.

/martha