SQL Server - granting permissions to an entire schema vs. object?

You can GRANT schema permissions that are effective for everything existing and everything that will exist in that schema.

Grant Schema Permissions

GRANT SELECT, INSERT, UPDATE, DELETE ON SCHEMA :: <schema> TO <user>;

Further to that, if you want to then deny permissions on a certain object within that schema, you can do.

Denying Object Permissions

DENY INSERT ON OBJECT::<schema>.<object> TO <user>;

To simplify a bit further, you can use roles to do the job that you are looking for.

Once you assign permissions to the role, you can just add users to the role. This way you dont have to manage permissions for individual users. The users inherit permissions granted to role.

Below is an example to get you started :

 -- Create the database role
CREATE ROLE TableSelector AUTHORIZATION [dbo]
GO
 ---- Grant access rights to a specific schema in the database
GRANT 
      SELECT, INSERT, UPDATE, DELETE, ALTER 

ON SCHEMA::dbo
      TO TableSelector 
GO

-- Add an existing user to the new role created 
EXEC sp_addrolemember 'TableSelector', 'MyDBUser'
GO

-- Revoke access rights on a schema from a role 
DENY ALTER  -- you can customize here ...
ON SCHEMA::dbo
      TO TableSelector