How to view VCF files without importing to Contacts App

Just QuickLook it (select in Finder and hit spacebar).

You might not see as much as you would if you open with a text editor, but it will be formatted like the cards in Contacts.

You can see a raw version of the contact card by doing Open With and choosing a text editor like TextMate, BBEdit or even TextEdit.

There are several applications in the Mac App Store for viewing vcf cards. A quick search for vcf yielded a number of options.