Michael, as others mentioned I would definitely go with the 18g brad nailer. This will handle the bulk of any finishing work you might have, and unless you were doing lots of finish work, would likely be all you ever need.
If you were doing enough trim work to warrant it, a 15g or 16g finish nailer would be in order. I prefer the slightly larger size of the 15g myself though do work with lots of guys with both.
If doing some finer finish work like putting small trims on, especially finished ones like in most installations of kitchen cabinetry, a 21g pin (or wire) nailer is really helpful. The pin nailer does not have great holding power as they have no heads, but it holds pieces in place while glue sets and leaves such a small hole it is really hard to detect and requires no filling.
I like Senco air guns. My framing gun, finish nailer, pin nailer and palm nailer are all Senco. They are very well built, and the service here is great. There are lots of other good brands too. My brad nailer is Porter Cable, and my narrow crown stapler & flooring nailer are Bostitch.
Last edited by BearLeeAlive; 05-14-2010 at 10:25 PM.