A web site is a popular way for artists to present their work, and it saves time if you can't make it to a in person meeting. It also saves space in your prospect's office, just in case they can't get around to looking at your printed portfolio or it gets lost in the mail.
Your web site should basically allow the prospect to interact with your work. It should be very user friendly and easy to navigate. Potential clients must know exactly where everything is that they want to see without being distracted by cumbersome banner ads or too much information. Try having an opening page that could include an engaging graphic or logo, maybe even an animated opening. You want to give your viewer the option of choosing to view your animation or going straight to the website itself. If you are using Macromedia Flash, make sure you put a clause at the beginning of the site stating "Click here for the Flash version of this site, or click here for the HTML version of the site."
If you choose to go right into the web site, including visually animated and/or visually engaging images is not a bad idea. An image gallery should be incorporated to allow the viewer to click on your images and see them enlarged. You must also use a feedback form on your contact page to capture their email and contact information. This works well for followup once your prospects show interest.