One minor nitpick, working closely with developers isn't always an option or necessarily a good idea. Working too closely makes it easier for assumptions and to get transferred over. I really like having testers who can take a completely fresh look at the application and find issues with stuff that I just didn't think to try because I know how the page was meant to be used.

In addition certain industries such as medical require testers to be separate from the development process entirely. On my current project for example we aren't allowed to bring in the test lead to our code reviews, we've discussed it.