I was told by my local building department that a modified round head or round head nail was acceptable.
This response is from the Kansas City, MO building code division and was made to my inquiry on this subject.
Honestly, we inspect fastener types, lengths and spacings very closely when we are performing the inspection of Fire-Rated assemblies, Shear-Wall or Braced-Wall assembelies and when inspecting an engineered supporting mechanism (such as a joist hanger). These all require specific fastening assembelies which have proven to perform up to certain standards according to testing labs (such as U.L.). Otherwise the framing members are simply fastened according to recognized methods and materials found in the 2006 IRC. If you check Table R602.3 you will see a series of footnotes at the bottom of the page (footnote (a) indicates that "Nail" is a general description and may be T-head modified round head or round head). I do not know if Modified Round Head would include Clipped Heads, but we are not going to critique, most likely, those installations that are usually counter-sunk anyway, and are many times located within members too far up in the structure to be seen clearly. We are counting the number of fasteners in these instances.
I think I'm going to go with the Porter Cable FC350A. I had been thinking about the Paslode F350S but didn't like the trigger and the fact that it didn't come with a case. The Senco 902XP is nice too but no case that I'm aware of, and the Paslode CF325 is too much for me at this point. Maybe I could get one in the future off of eBay or at a Paslode Outlet Store.