Good website design delivers quality content with simplicity and grace. Design should be a function of the needs and desires of the targeted audience. And, while your presentation shouldn't be boring, fancy effects and images that aren't necessary should be avoided. The key here is to know who is going to be visiting your site and design it accordingly. A busy page with unnecessary animation only distracts your visitors from the message you are trying to deliver.
On the other hand, some action oriented products, many targeted toward the youth market, may dictate the use of animated display and demonstration along with a color scheme that suits their tastes. As Internet Browsers become more sophisticated and wider bandwidths reach a larger market, designers are tempted to offer ever more compelling content. Powerful presentations can be created with Macromedia Flash "movies." Flash includes ActionScript, similar to JavaScript, allowing the creation of dynamic graphical user interfaces. Even here, restraint is essential as visitors will move on if distracted from the message, find navigation difficult or are subjected to excessive download times.
The theme of the website should complement the message being conveyed to the audience and be consistent with the identity developed by the company in other media presentations including logos, trademarks and color schemes. A financial services firm will want to present a rock-solid image with subdued colors much different than a florist with vibrant colors themes and product images. In either case color schemes and images should not assault the eye. Neither should it be so subdued it doesn't attract attention. Rather, it should invite the visitor to it's content.
While there are many additional design considerations, the above covers much of what should be considered before meeting with the web designer. Any promotional materials that represent content or design the company has adopted will provide valuable insight. Product catalogs are often an invaluable resource for constructing the layout for commerce sites.