Necessary Gear?

I've been slacking off on running for a while, but now that I'm getting in better shape from bicycle commuting, I think it's time to get back to it. And if I'm going to get serious about running again, I have to make sure I've got the right equipment.
However, I've found myself wondering what, exactly, do I really need to run.

When I first got into running, years ago, I thought I needed all sorts of high tech equipment

 But after a while, I came to think that all you need is a decent pair of running shoes

 

But, later in life, I realized that the shoes don't even matter that much, that a few hundred millenia have prepared human beings to run as they are 

So I got to thinking "well, all you really need to run is a pair of feet!

Um... or maybe I'm just overthinking things.