Duracell definitely has the bunnies.
They are the better batteries too.
Although I bought some National (part of Matsushita, the company responsible for Panasonic and Technics brands) D cells a couple of years ago from a cheapo shop.
I put them in a boombox at work that gets left on all day, and they're still going strong.
They cost 80 pence a pair, as opposed to about £3.50 for Duracell or Energizer.
Encouraged by this, I bought some different sized National batteries for different things (clock, minidisc player, kids toys, etc.).
They were all crap.