I've always considered "touring bikes" to be the most versatile models out there for anything but competitive road races or hardcore mountain biking
Commute, touring, utility, city, urban, recreational, fun, hybrid, you name it... a touring bike will provide you with all your needs for many many years as long as it is properly fitted and of a good built!

"Surely LHT" is definitely one of these models, the "Dawes Galaxy" is another one and of course the "Trek 520" too.
I am more into Cannondale: I personally ordered the "Traveller Classic" that I am waiting to receive impatiently!

... And many cyclist use a cyclocross as a sportier and sometimes cheaper alternative to a great success

Depending on the touring bike model and brand, some are more road oriented with 700x28 tires and road gearing; while others are on the other side of the scale with mountain bike gearing and tires up to 700x37. But in both cases they work fantastically well on gravel and dirt.

I would recommend the 700x32 as mentioned above, that's the perfect balance for me.

PS: Beware of pure road cyclists/athletes that consider anything above 15lb to be slow and heavy!
If I am not wrong, you should be averaging between 14mph and 17mph on your commute if not less.