Interesting question, Greg. It depends a lot on the location but in general I’ll take a good hotel at a reasonable rate in the neighborhood where I want to stay over a free breakfast.
In my limited experience it seems that free breakfast is more common in places where there’s greater competition (and less business) among hotels, and is sometimes a perk offered at less-desirable or older hotels.
If I’m in a suburban sprawl area (which definitely would be on the company’s dime and not on mine) I want some breakfast onsite, and a decent free buffet is a perk (I’ve also seen a couple of older places that give guests a coupon for breakfast in the dining room). In a city I want coffee in my room (I’d prefer not to go down to the lobby, but it’s not a deal-breaker), but after that I’d just as soon hit the streets and find where the locals eat.