kind of a group reply
On a PCB the stray inductance of the traces is more of a concern than the inductance of the cap although you generally would use a low ESR cap to suppress higher frequencies, normally a tant cap. I work in mixed signal audio / digital boards, not in RF tho and some wierd rules can apply.
EMI is generally caused by very poor routing of traces and/or grounded schemes on the board and is possible here, i.e. not providing a returnground path under a high speed trace forces the return current to go in a big loop creating a large inductance (antenna)
Not really sure what you mean about the RC filter....i assumeyour talking about the supply lines, generally don't want to put series resistors on the power supply lines, causes voltage drops proportional to current draw :p
filtering is usually done with an LC filter to cut high frequencies or companies like murata make EMI parts that contain prebuilt LC filters for cleaning up supply lines
The capacitance between the ground plane and power plane in an average PCB is large enough to soak up high frequency noise to a ceratain extent tho you would normally place a 10uF cap and a 0.1uF cap as each IC to provide additional filtering. Sections that need super clean power are normally isolated and only connected to the main supply via a choke coil providing filtering of high frequency noise. (example an audio ADC that needs 3.3V and a microcontroller would not share a single 3.3V supply plane)
-x