Inductive choke with bypass capacitors?
I'm more for an RC-filter than an LC, and the resonance is one reason. You have a high noise suppression above the resonance frequency, but hardly anything below. If you then want a low cutoff-frequency the inductor may become impractically large.  

I've seen circuits where EMI ferrite beads are used, but these are almost useless. They do have a near zero impedance at DC, but their peak impedance (often a few hundred ohms) often lies above 50 MHz, so much noise will hardly be filtered.

But the RC-filter isn't ideal: the resistor will have a voltage drop, and if you choose a low resistance you'll need a quite large capacitor to keep the low cutoff-frequency. An RC-filter may be acceptable if the microcontroller won't need much power (don't forget what it sources to its I/Os!), but at 5 mA a 100 &Omega; will already drop 500 mV, which is fine if the input voltage is chosen a bit high especially for this, but which you maybe can't afford.