Unless you or your business are like a large worldwide corporation you don't need to spend the additional money trying to "wow" your web site visitors. Your designer must be able to do more than just impressive graphics; they must be able to create content on the pages in a logical and coherent fashion which is practical, readable and understandable for your visitors. If they are good, they will create a design that balances the “show stopping” part with good page form and site functionality. You should also know if they have a good understanding of HTML coding, branding and marketing, search engine ranking, placement, indexing and submission. Without these qualifications your site is surely failed from the start.