Mine would cost £700ish to replace, compared with £300 for my mountain bike.
It is my only road bike, it gets 3 or 4 thousand miles a year of riding, and that would be a right old pain on a mountain bike.
It has a hub dynamo, lights, great big rear saddlebag thing, mudguards etc. and is set up very much for commuting, shopping etc. If I did road biking seriously, I'd probably want something else too.
It's insured on my household insurance, as long as it's locked up (costs me £30 a year or so), and it lives in my office at work, and somewhere quite secure at home, but I do lock it up and leave it in town, or at the shops or wherever.
Joe