Door stop?  

Puk

Stone
.

Puk is slippery on wood/stone floors
I ended up returning mine. I use a plain old fashioned black rubber wedge type. I also have a couple of river stones! Simple is better, less is more, etc...

Interesting
You would think the Puk would have a (optional) rubberized pad on the bottom side... Of course, it could be easily added.

I have one of these,...
I have one of these, designed by Ed Carpenter. Just don't stub your toe on it!!

Mahagany wedge. Make sure...
Mahagany wedge. Make sure it bears the correct Mahogany Association Number.....otherwise it worthless!
The wedge below actually is mahogany...and a nice simple option

Blomus makes some nice one.
The two cylindrical stops have non-slip bases.
My favorite is the wedge with the built-in loop for hanging on the doorknob.
http://www.thestainlesssteelstore.com/Blomus-Stainless-Steel-Door-Wedge-...

And...
Of course, there's also this alternative to the cast-iron rooster, if you can afford it and can still find it anywhere.

This one is pretty cool...
Albeit a tad large...

Good idea, Woodywood.
What are those multicolored things in the righthand photo, though?

^Literally
ROTFLMFAO!^

Rehang the door
A properly hung door will stay put however widely you open it. You can hang a door straight in a saggy house.
That said, I did it once but have never gotten around to fixing the others in the house. I think the doorstops above are all very nice and are a much easier solution than rehanging a door. But dang, that perfectly hung door was sweet.

Spanky, apparently you do not live with
cats, dogs, children or any other domestic animals. No door in the world no matter how well hung (snicker, snort, giggle)will stay open in the prescence of two and four legged beasties. A door stop works well for the lifespan of the four legged varieties and long enough to reach 'you know better' for the two legged ones.