When I started living (mostly) car free I bought a 7.5FX to complement the specialized mtb with skinnies. Although it's more expensive (~$900 retail) this is definitely a better choice than the typical hybrid which has slow cruddy mountain bike components. Especially since the new TREK 7.5FX comes with r440 road shifters, road cranks, and road FD. The r440 is a great part because you can purchase the r770 right shifter (~$70) and upgrade to 10-speed at a later date. I road this 7.5FX to death and Trek kindly replaced it with a 7.9FX frame for free. Its now 105/ultegra, bb7 front disc, and not a single piece of the original 7.5FX left!

IMO, the only reason to run larger tires is comfort and off road compatibility. I live in PDX and run 23 mm in the summer and 25 in the rainy winter.