Site performance is one of those oft overlooked components of a website that's more important then many think. In the scope of a web design project, typical requests tend to focus on looks and functionality. Rarely do conversations turn to requests for streamlined performance.
Besides the obvious usability reasons for wanting a fast, high performance Drupal website, Google has begun to emphasize the idea of site speed as an important factor in search rankings.
Look for hosting providers that provide you with the ability to add additional functionality to your server and give you plenty of optimization options.