Nice, I just bought myself 2 Super Capacitors for $18 bucks + P&P

[system]

No, that would be in parrallel.

If you wire two capacitors in series, the voltage is shared between then proportionally to their capacitance (Q = VC where Q is the charge on the capacitor, which would be the same amount on each). If they both have the same capacitance, then the voltage (in this case 5v) would be shared between them equally, so each would see only 2.5V. The maximum allowed would be 5.4V, not taking into account any small difference is capacitance. 5V is less than this, however 5V nominal could have voltage spikes or noise which may expose the capacitors to more than they are rated for.

I could use a ZenerDiode to clamp it as closely possible to 5v without going over, a linear regulator would not cut it, too much of a low drop out, a switching regulator would be pushing it too, I think a Zener 1 watt would be the best way to go... or simply place a power diode, let the voltage drop take care of the extra voltage that "could" take place...