All of me portys on my macbook have lost it (it enjoys whoring around with cables of different ethnicity's), but my display port on my macbook was the last to loose it maybe 6 months ago. Good lil guy.
On my iMac quite a few USBs are actually virgins! Thats what you get when its a family machine.
On my mini, nothing is. All ports where raped of their innocence the second it was out of the box, twas my first mac after all.
This thread title reeks of the Mittens posts of yore. I miss him, in a weird sort of way... BUT to answer the question:
Firefire ports. Both are such prudes they belong in a convent. Well, and the Express-thingie slot. But it's got a little metal door that snaps up and down.. I once poked around in that out of unashamed curiosity, but nothing ever came of it.