I happen to love the Resume feature in Mac OS 10.7, but many people have shared their feedback that it would be great to not have everything resume in place upon startup.
It makes sense to want a choice, because many times, you may be finished with a window when you go to shut down or restart.
To discard open windows, hold down the Option key when you quit and you’ll be able to restart your workflow without extra clutter. To change the default, go to System Preferences where you can toggle the full resume off.