Elephant isn't much heavier or stiffer than bullhide. In fact, depending on the tanning process, elephant can be really supple from the very start. I have a couple of pairs that have never given me a moment's trouble. I highly recommend elephant hide as a boot leather choice.
On the other hand, if you're looking for something for regular everyday wear, I wouldn't recommend water buffalo or any reptile hide. Water buffalo is pretty light and needs a backing leather to be strong enough for boots. It also scuffs really easily, in my experience. All reptile hides, whether snake, lizard, alligator or crocodile, tend to split between the scales. You'll have to be really careful with keeping them clean and conditioned. Snake is also pretty thin and needs a backing leather to work in boots.
Strong, good looking leather for dressier boots would be kangaroo, ostrich (you can get either full quill or smooth) or a simple calf skin. Depending on the rest of the details, you can make a pretty dressy boot with elephant or shark, despite the texture. Talking with your bootmaker will help narrow down the best choice for your needs.
Be careful with that Top 25 list, too. It's from 2002 and much of the information is out of date. Tex Coleman is semi-retired and has moved to Abilene, Maida's has either relocated or closed, J.L. Mercer died and the shop closed, Rusty Franklin retired and sold his shop to Robert Brest (who makes great quality boots, by the way), M.L. Leddy only has their factory in San Angelo and runs all their sales out of the Ft. Worth store, and there are probably more changes that I don't know about right off the top of my head.