Current for Arduino UNO3 and battery to power it

Hello, I want to use a battery to power the UNO 3. Ideally last relatively reasonable but not too big and heavy. I know that the voltage range for the UNO 3 is 7-12V. What is the recommended current range? Is the rectangular 9V battery that can be bought easily a good choice?

I'd go with 3xAA and power the board thru the 5V header pin. Add a diode (1N4001) from 5V (anode) to Vin (cathode) to avoid reverse driving the 5V regulator and damaging it.
Or 3 Cs, or 3 Ds.
Powering from >7.5V thru the barrel jack just dissipates battery power as heat.

CrossRoads:
I'd go with 3xAA and power the board thru the 5V header pin. Add a diode (1N4001) from 5V (anode) to Vin (cathode) to avoid reverse driving the 5V regulator and damaging it.
Or 3 Cs, or 3 Ds.
Powering from >7.5V thru the barrel jack just dissipates battery power as heat.

Thanks. Is 1N4007 equally good? I can't find 1N4001 in a nearby store.