I've tried road bikes but I've decided that, possibly, the same odd configuration of back muscles (or lack thereof) that makes it impossble for me to sit on the floor well, and makes me thoroughly grumpy trying to do sitting poses in yoga, means I'm simply not comfortable in the "road bike" position, regardless of the assorted angles.
I ride my 2002 7500FX on most of my medium and long rides (RAIN ride - 160 miles, GITAP 2005- 450 miles in a week); I went back to my Giant Hybrid for long tours because it's a little more comfy (steel frame? the *perfect* fit?).
It's worth spending time exploring fit and experimenting. My hybrids are less aerodynamic; that's the main disadvantage (but it essentially disappears in a paceline except for when I'm in front). I don't usually ride with the "front group," though.
So I'd say if that extra 10% in speed is important (and there are lots of very good reasons for that ) keep experimenting with road bikes. (If it's important to have a "good" bike, too.) If it's the distance, though, the 7500FX can do the job... or think out of the box and look for things like moustache handlebars or things that change the position to be more like your hybrid fit. But maybe those dollars could go to something else fun, like a tour :-)
(My LBS guy has designed his own bike an dnow it's got moustache handlebars... he knows I've been lusting after that bike already...)