Adobe Acrobat takes forever to load (with “forever” being defined as 4-5 seconds), so I wanted all my PDFs to open in Preview, by default. The thread above explains how to do it.

1. Select a PDF file in the Finder
2. Select “Get Info” from the File menu (or hit Cmd-I)
3. Set “Open With” to Preview
4. Click the “Change All” button to make this the default for all PDFs