The water bottle has undergone quite a metamorphosis. Its humble beginnings were as a little plastic bottle with a tiny orifice at the top that could be coerced into delivering fluid only by squeezing for all you were worth (which generally isn't much at the end of a ride in my case). It generally had a little cap attached with a plastic strap that you had to figure out how to get off, and put back on when you were done without losing stride. The first great improvement was making the bottle bigger. Not too much rocket science involved in that one, but it took the bicycling community about 20 years to come up with it. Next they improved the spout, with a push-pull thing rather than the little cap the old ones had. They made that bigger too, so that you could actually get a decent stream of water out of it without giving yourself a hernia, and could open and close it with your teeth.
A recent innovation is the flip cap dome sort of thing that covers the actual nipple, sort of a condom for your water bottle. This strikes me as somewhat over fastidious, but I am reminded of a ride through Great Brook Farm. It was pretty muddy and riders coming in ended up with mud spattered on their water bottles. What they didn't realize was that a flock of geese had been tromping around, and hadn't bothered to use the outhouse. Several riders reported an additional and not altogether pleasant flavor. In that instance the water bottle condom would have been a good idea.
Then the Camelbak came on the scene. This really revolutionized the art of water carrying. Now you could transport an almost limitless supply of fluid (if you're not concerned about spinal injury). Next came the Camelbak with pockets. Now, in addition to throwing away your water bottle cage (which you really couldn't do, since now it held your pump bracket on), you could dispense with the tiny saddle bag you used to hold your spare tube and dime to call a cab. The logical progression to this is to carry a backpack with a five gallon jerry jug and a garden hose attached. Kalahari desert, here I come. It's hard to imagine getting into an aerodynamic tuck when you look like Quasimodo, though.
The other interesting product in the water bottle arena was a plastic tank that fits into your aero bars. Looks a lot like a Volkwagen gas tank (holds a lot more, too). I can see pulling into a Seven-Eleven with one of these, saying "Fill 'er up, Gatorade."
Water bottle is actually somewhat of a misnomer. People don't put water into them any more. They should more aptly be called Energy Fluid Bottles. I recently had someone ask me what was in my water bottle. "Water," I said. Words cannot describe the look of horror and disgust on his face. I admitted that sometimes I drank Gatorade. This did not go down any better, and I was beginning to feel very low on the evolutionary scale indeed. Well, it turns out that he worked for a company that made a new space age sports drink that would enable your basic Casper Milquetoast to leap tall buildings at a single bound. I felt a little better after that, being as he wasn't exactly your man on the street (who would probably expect your bottle to be filled with beer).