trim work and nailers?
 

I need to install chair rail, molding around doors and windows and crown molding... what would the best nailer to use be (what type?) and what size nails or staples would you suggest?

Right now I have these nailers:

Framing - (obviously too big for the job)...
Finish nailer that does 16g
Brad nailer / Stapler - 18g
Pin nailer - 23g

also have one of those neat palm nailers that says it can do 6d to 16d

never used a nailer before, so this is a learning curve for me... thanks!

I would use:
chair rail: 16 ga
molding around doors and windows: 16 ga into trimmers, 18 ga into jamb
crown molding: 16 ga
Glue and pin your miters
Most mouldings have a shadow line, put the nail there, it will be less noticeable. I try for 1" to 1½" of a nail into wood. So for a 1/2" thick door casing over 1/2" drywall I'd use either 2" or 2½" nails.
For wood trim, acclimate it for one week. Stain or prime your moulding prior to installation. It is especially important for stain grade as you can match the grain and tone. Use unmatched pieces inside of closets.

what excatly do you mean by pin the miters? use the pin nailer to hold them?

Yes shoot a pin from one casing through the miter into the other. It will act as a clamp until the glue dries.

was trying out the nailers last night, definatly love them compared to the old hand hammering way...

have one question though.... should crown be "Stapled" or nailed? the gun's manual suggests stapling crown, but what is most common?

Use your finish gun on the crown.