Palm Nailer
We were originally planning to buy a framing nailer for the interior walls, but a suggestion by a
friend of mine caused us to go with a palm nailer instead.  It has turned out to be one of the best
decisions we've made, as the palm nailer is quick, easy to use, and very versatile.  The nailer
handles a wide variety of nail sizes interchangeably
(we've been using mostly 10D's and 16D's),
and it gets into some really tight spaces that a framing nailer or a normal hammer wouldn't be
able to even get near.  It can be used with either hand, which really helps sometimes when you're
up at the top of a ladder and need to get to an awkward spot.

Some palm nailers drive nails with a single powerful stroke, but his particular model uses lots of
really short, sharp strokes.  This seems to give better control, particularly when toenailing.  The
model we bought (we actually bought two of them) is made by Porter-Cable and was the highest
rated of the brands we could find.
 It has held up excellently.

The DeWalt compressor is a standard 4-gallon, 2.5 horsepower model and it more than keeps up
with the nailer.  It's a heavy sucker, though, and I'm getting tired of lugging it back and forth at
the beginning and end of each work day.
Addendum:  We (just my wife and I) finished the framing all of the interior walls of the house in
about three weeks.  It was a piece of cake, thanks to these two tools (plus a saw, of course).