Best Practices for an Unsubscribe Page?

Those are all good choices. The key is to offer choice by Type of Communication and Channel of Communication.

You could also make an Offer on the page to avoid an unsubscribe. Or maybe an offer on the confirmation page.

Hi Courtney -

We (as a company) are relatively new to Marketo, however, personally I am a veteran in many M.A. tools, and one of the priorities I had coming into this position was to establish standards, and one was the unsubscribe/opt-out.  We are in the midst of redesigning our company website, so until that is set, I just took a minimalist approach to the layout and did everything in Marketo.  We have an Unsubscribe and preference center that tie together.

Unsubscribe - http://pages.storagecraft.com/unsubscribe.html (if you click the check box, we ask a few lighthearted questions)
Unsubscribe Confirm  - http://pages.storagecraft.com/unsubscribe_confirm.html
Preference Center - http://pages.storagecraft.com/preferences.html

Feel free to reach out with any questions.  Hope this helps.

We took a pretty simple approach as well. Here is an example of our unsubscribe page. 

http://info.webmdhealthservices.com/UnsubscribePage

We allow people to update their preferences and choose a category they want to recieve or unsubscribe from everything.

Erin