I've read that the voltage regulator takes alot of power too, is it apart of the ftdi chip?
In general linear voltage regs do use a lot of power.
If your Arduino is running from the USB there will be no wasted power because the 5v is connected directly through to the PC. The FTDI does regulate the USB 5v down to 3v3 so if you're using that there will be losses.
If you're using the DC jack then the on-board regulator will waste power, more or less according to the level of VIN. In this case the best thing to do is to reduce VIN as much as possible, say to 7v. If it's at 20v then things will get hot and that means a lot of power is being wasted.
Of course no matter what you do power supply-wise the voltage is being reduced by something somewhere?
The most efficient thing to do is bypass all the regs and run the board directly from batteries.
It's interesting that ruggedcircuits measured 25mA, I quote from an email I recently got from an FTDI tech
The device itself requires 25mA.
We were talking about their integrated USB-serial cables, but the electronics would be the same as that implemented on the Arduino. This implies that just about ALL the power consumed is by the FTDI chip.
Therefore if your final product is a stand-alone 328 without the USB then you'll be down in the micro Amps I would think.