How to restrain this soft latching power switch from eating too much current?
The FETs can hog current upto 500 mA. For higher load, it is very easy to find FETs with low Vgs threshold. Before pressing the switch SW1, M1 will be off since Vgs is zero. Once switch is pressed, M3 turns on followed by M1 followed by M2. M2 holds the ground to gate of M1 there onwards. When SW2 is pressed, M2 releases the Gate of M1, making the Vgs of M1 zero again, thereby cutting out 5V_OUT. 7805_5V is regulator output. Needless to say, the switch section will consume significantly less current to be suitable for portable applications.  I hope, power dissipation across 7805 is looked upon.  

(Vin - 5V)/0.7 Watts








simulate this circuit &ndash; Schematic created using CircuitLab