MVC 3/EF repository pattern and proper data access
if (MembershipService.ValidateUser(model.UserName, model.Password))
{
    User newUser = new User();

    using (AccountRepository repo = new AccountRepository())
    {
         newUser = repo.GetUser(model.UserName);
         ...
    }
}

public override bool ValidateUser(string username, string password)
{
    using (AccountRepository repo = new AccountRepository())
    {
        try
        {
            if (string.IsNullOrEmpty(password.Trim()) || string.IsNullOrEmpty(username.Trim()))
                return false;

            string hash = FormsAuthentication.HashPasswordForStoringInConfigFile(password.Trim(), "md5");

            bool exists = false;

            exists = repo.UserExists(username, hash);

            return exists;
        }catch{
            return false;
        }
    }
}

public User GetUser(string userName)
    {
        try
        {
            return entities.Users.SingleOrDefault(user => user.UserName == userName);
        }
        catch (Exception Ex)
        {
            throw new Exception("An error occurred: " + Ex.Message);
        }
    }

public bool UserExists(string userName, string userPassword)
 {
        if (userName == "" || userPassword == "")
            throw new ArgumentException(InvalidUsernamePassword);

        try
        {
            bool exists = (entities.Users.SingleOrDefault(u => u.UserName == userName && u.Password == userPassword) != null);
            return exists;
        }
        catch (Exception Ex)
        {
            throw new Exception("An error occurred: " + Ex.Message);
        }
    }

public class AccountRepository : IDisposable
    {
         private DbContext entities;

         public AccountRepository()
         {
            entities = new DbContext();
         }

         ...

         public void Dispose()
         {
            entities.Dispose();
         }
    }

var user = userRepository.GetUser("KallDrexx");
var companies = companyRepository.GetCompaniesForUser(user.Id);

public class UserRepository
{
    public User GetUser(string userName)
    {
        // GetUser code
    }

    public User GetUserWithCompanies(string userName)
    {
        // query code here
    }
}

public class MyController : Controller
{
    private Entities context = new Entities();

    ...

    public override void Dispose()
    {
        context.Dispose();
    }
}

repository.Users.GetUser(userName);

private UserRepository users;

public UserRepository Users
{
    get
    {
        If (users == null)
        {
            users = new UserRepository(this);
        }
        return users;
    }
}

repository.Users.GetUser(userName);

UserQuery query = new UserQuery(repository.Users);

repository.Area.Query(value1, value2, ...);

AreaQuery query = new AreaQuery { Property1 = value1, ... };