When a SharePoint site is created, by default 3 SharePoint groups are created
Site Owners - Full control
Site Members - Contribute
Site Visitors - Read
Below are the permissions you get when you are a Site Owner (Full Control)
List Permissions
Manage Lists - Create and delete lists, add or remove columns in a list, and add or remove public views of a list.
Override Check Out - Discard or check in a document which is checked out to another user.
Add Items - Add items to lists and add documents to document libraries.
Edit Items - Edit items in lists, edit documents in document libraries, and customize Web Part Pages in document libraries.
Delete Items - Delete items from a list and documents from a document library.
View Items - View items in lists and documents in document libraries.
Approve Items - Approve a minor version of a list item or document.
Open Items - View the source of documents with server-side file handlers.
View Versions - View past versions of a list item or document.
Delete Versions - Delete past versions of a list item or document.
Create Alerts - Create alerts.
View Application Pages - View forms, views, and application pages. Enumerate lists.
Site Permissions
Manage Permissions - Create and change permission levels on the Web site and assign permissions to users and groups.
View Web Analytics Data - View reports on Web site usage.
Create Subsites - Create subsites such as team sites, Meeting Workspace sites, and Document Workspace sites.
Manage Web Site - Grants the ability to perform all administration tasks for the Web site as well as manage content.
Add and Customize Pages - Add, change, or delete HTML pages or Web Part Pages, and edit the Web site using a Microsoft SharePoint Foundation-compatible editor.
Apply Themes and Borders - Apply a theme or borders to the entire Web site.
Apply Style Sheets - Apply a style sheet (.CSS file) to the Web site.
Create Groups - Create a group of users that can be used anywhere within the site collection.
Browse Directories - Enumerate files and folders in a Web site using SharePoint Designer and Web DAV interfaces.
View Pages - View pages in a Web site.
Enumerate Permissions - Enumerate permissions on the Web site, list, folder, document, or list item.
Browse User Information - View information about users of the Web site.
Manage Alerts - Manage alerts for all users of the Web site.
Use Remote Interfaces - Use SOAP, Web DAV, the Client Object Model or SharePoint Designer interfaces to access the Web site.
Use Client Integration Features - Use features which launch client applications. Without this permission, users will have to work on documents locally and upload their changes.
Open - Allows users to open a Web site, list, or folder in order to access items inside that container.
Edit Personal User Information - Allows a user to change his or her own user information, such as adding a picture.
Personal Permissions
Manage Personal Views - Create, change, and delete personal views of lists.
Add/Remove Personal Web Parts - Add or remove personal Web Parts on a Web Part Page.
Update Personal Web Parts - Update Web Parts to display personalized information.