Vincent Flanders is an expert on bad web sites. He's been writing about them since 1996 and has never lacked for bad examples to chronicle. While you're reading through his post, "The Biggest Web Design Mistakes of 2004," give some thought to the rest of your marketing materials. Many of the mistakes he discusses in web site design are often repeated in other pieces of marketing collateral.
I would also recommend that someone in your marketing group should be subscribed to Jared Spool's newsletter for web designers, usability specialists, and information architects.