As someone who put around 2K miles on a Hybrid before moving to a Road Bike (Specialized Secteur), I can tell you that most of this pro-hybrid thread is mis-informed.
Myth: Hybrids are more comfortable.
My Experience: Hybrids are more comfortable for the first 30 minutes. After that, the better weight distribution of a road bike wins out for comfort assuming we're not talking about racing geometry (I'm riding a Secteur, which has an endurance geometry). Road bike hand position is also more comfortable as it promotes a straight wrist position, where as hybrid bars require wrists to be flexed. I very rarely use the drops and stay mostly on the hoods, for reference.
Myth: Front suspension and bigger tires = smoother ride.
My Experience: Not necessarily and not nearly as much as you think. Front suspension means more wasted effort going up hills due to the springiness and added weight. My bike has Front and Rear Zerts inserts to smooth out road vibration, and it does an amazing job. There are only a few rare occasions I miss my hybrid's bigger tires (grooved pavement is one of them), but most roads, even blue chip roads, are just as smooth.
Myth: Going faster doesn't matter to a casual cyclist
My Experience: I'm no racer nor do I want to be, but adding around 2Mph of speed and losing 12 pounds of bike for free changed my riding a LOT. It opened up a ton of new routes and I avoided hills a lot less. More routes=more enjoyment.
Myth: Road bikes are hard on your back
My Experience: I have lower back issues. I have found that my road bike is actually easier on my back as it takes weight off of my lower spine that sitting more upright imposes and the movements generated from the riding position keep my back loose. However, it might depend on what exactly is wrong with your back so YMMV.
Now, where hybrid win, hands down, is price. I paid $279 at Dicks for my hybrid (Diamondback Edgewood) and for 2 years it was my gateway drug, so as a first bike to see if you are interested in going further in the hobby they are awesome.
But the first time I test-rode my current road bike it was truly eye-opening, like I had been riding with the brake on and now I was free.