Battery operated 3.3V power supply design

What is the best LDO regulator or other circuitry for a battery operated 3.3V product. We could just use two batteries and run it on 3V but there is no reverse polarity protection. If we use three batteries we have the headroom for a diode or a LDO that that has reverse polarity protection if there is a LDO with that capability. Obviously power loss is also a concern.

Here is a link to some 3.3V LDO options.

Depending on the input varies which we are looking at. You will also see that we have some with a reverse polarity option. this is listed under protection features at the top of the screen.