I think the most important thing that makes advertising artful, is when it is not necessarily about what it's about. Essentially all that an ad needs to do is get your attention, and tell you about a product or service. It is when ads go above and beyond that standard that they become art.
One company that does a really good job of this is Bank of America. Here is a commercial advertising online banking. But do they simply tell you about online banking, no! They illustrate a lifestyle free from things like ATMs.
Another company that does a great job of advertising more than just its products is Target. I really love their "Brand New Day" spot because it is all how people are becoming more frugal, but in such an optimistic way.
One of my current favorite spots thats running is the Prius harmony commercial. They really took your basic car commercial of driving through nature, to a whole new level. I think its inventive and creative.
