I will usually order breakfast from room service when travelling on business and it's usually a time issue. While waiting for my breakfast, I can also get work done and do any packing, catch up on news make phone calls, breakfast arrives, I can chow down and then get out the door and on my way.

When travelling on my dime, I usually like to search around for a really great breakfast place and I'll have the time to do that.

Rarely order dinner, unless I have extreme circumstances, like late arrival or something like that.

The mark up on those meals are outrageous, but the only hotel I have ever stayed where the room service prices were reasonable and the food was excellent was the Movenpick in AMS. I actually preferred some of those meals over the local fare.