In my experience working with some of the top agencies in London, a lot of emphasis is put on developing award-winning creative. While it's great publicity for the agency (and sometimes the client too), I would advise clients to consider whether an appropriate portion of their budget is being spent on creative development.
A long-standing tenet of direct marketing is that creative is only responsible for 20% of a campaign's success. The list and offer are responsible for 40% each. It's also a good thing for account people to keep in mind when they are dealing with the demands of the creative department.
But what about the percentages for online media? For e-mail marketing, the percentages are the same. For web sites, where there is no "list", it's up for debate. But consider the no-frills pages on Wikipedia and Craigslist or the shoddy design of MySpace. The creative wasn't king for these success stories.