I stumbled into a 'cross bike as my first "serious" bike, on advice from the previous owner. My style is: mostly road, some trails, do not want to hoist heavy MTB.
I now have it set up with slicks, as I find myself on the road most of the time. Probably when winter rolls around I'll be on the trails again, and probably switch back over to touring or knobby tires.
I suppose if I had it to do over again, with unlimited amounts of cash, I'd go for a pure road bike and a separate MTB for trails. It's possible to set up a regular road bike for trail use. The 'cross bike is certainly not a bad choice; I love mine. I'm not sure it was the best choice, but I didn't really have a lot of choice.