The 2 pin base is the GU24 base which has been labelled as "energy efficient" as you cannot fit a E26 base (edison screw in base) incandescent bulb.

Yes, get the standard E26 base as there is no difference.

AND, because the way CA Title 24 is implemented to preclude the use of edison base lamping.
Then along comes CREE.
Yes those dastardly entrepenures. How dare they subvert those well meaning tree hugging, berkenstock wearing, nanny-state liberals.

Thank you so much for the replies. I was naturally drawn to the Energy Star rated fixtures but didn't realize that many required GU24 light bulbs which were much more expensive than E24 CFL's... I thought surely I was missing something that GU24s offered better performance etc. Good thing I checked in with you guys. Thank you!