Given the two scenarios, which code is best practice and why?

Autorelease

loginButton = [[[UIBarButtonItem alloc] initWithTitle:@"Login" 
                                                style:UIBarButtonItemStylePlain 
                                                target:self 
                                                action:@selector(loginButtonClicked:)]
                                                autorelease];
self.navigationItem.rightBarButtonItem = loginButton;

or

Release

loginButton = [[UIBarButtonItem alloc] initWithTitle:@"Login" 
                                                style:UIBarButtonItemStylePlain 
                                                target:self 
                                                action:@selector(loginButtonClicked:)];
self.navigationItem.rightBarButtonItem = loginButton;
[loginButton release];