Additionally:



Two other methods include:

Fillet
You'll get a nice look as expected, but the top may be left majorly flat and you sometimes end up with the multiple panels as Fillet negotiated the shape.

Rail-Revolve (Michael's Alien Foot Style)
You've seen Michael use this method for making the foot on the alien in his tutorial.
If you use only half of the bottom ring and perform a Rail Revolve using the side profile (that reaches from one side to the other)
You'll get a very nice shape along with a good clean top point structure.