What are the roles in Sharepoint ?

First, lets talk about the five roles within SharePoint:

• Information Worker - People who use the site. They can be in charge of an individual list, maybe even a site, but no more than that. Most times they just have enough privilege to add documents to your document library and Check-in / Check-out items.
• SharePoint Site Admin - People who are delegated the responsibility of maintaining a site collection. These users are very much like a Power Users group within SharePoint. They have access to create additional subsites, create lists, restore documents using the Recycle Bin for other users, and so on.
• SharePoint Server Admin - People who are responsible for creating additional Web Applications, maintaining existing ones, enforcing Quotas on site collections, verifying backups, etc. Overall they are in charge of provisioning SharePoint and maintaining a healthy SharePoint environment.
• SharePoint Designer - People who are delegated the responsibility of customizing the SharePoint user experience, but do so in non-developer way. Typically these people are in charge of creating workflows using SharePoint Designer, adding content through the content management interface or through SharePoint Designer, and possibly are in charge of updating Layout pages or master pages to give your sites a more company intranet feel than a SharePoint intranet feel.
• SharePoint Developer - People who are delegated the responsibility of extending the capabilities of SharePoint via solution packages and features. Solution packages and features include things like: customized lists, customized site definitions, webparts, custom content types, extremely customized workflows, custom menus, etc.

With that being said, The SharePoint Consultant would most likely take the role of SharePoint Server Admin. They might (until somebody internally can be brought up to speed) be the SharePoint Site Admin as well. Possibly (as in my case) they might even be the SharePoint Developer role as well, but don't count on that. There aren't that many developers who understand the server-side of things, and vice-versa. This is especially true with SharePoint.