In the context of flight / hotel / car / etc., I think hotel-building is very clear. In fact, much clearer than a bed -- after all, having an airline seat represent a plane would be quite confusing, and having a bed represent a hotel is no clearer.

However, outside the context of other reservation-related icons, I agree that the "building" icon is lacking in specificity. The bed icon is slightly better, but still by no means good. It could just as easily mean sleeptime or rest, as opposed to daytime or work.

It's a shame there are no symbols or architecture inherently associated with hotels. Maybe that's why they tend to feel so anonymous and devoid of any soul...