Before the web there was print design and that is kind of where we all came from. Modern media design is a bit more challenging because of it's dynamic nature, yet when it works the best designs look simple and effortless.
Most modern sites are now based on a CMS. Companies want to manage their own site but they still want them to look good. That is why well constructed CSS are so important. Not only to control the continuity of the site but also to allow the site editors enough freedom to express themselves.
At bee2 we stick to a few core principles that make sure our sites always look good. It might sound odd but we always approach design with the end user in mind rather than the client. Digital design is an unsupported media so the public only look at your site because they like it (or you have some incredible offer!).
Usability; this is the other key factor that makes a site good. It doesn't matter how cool and trendy your new site is, if the users can't find the content they want.
If you want to work with bee2 but use your own designers this is fine. Just show us what you are planning on doing and we will let you realise your aims.