1. Old fashion wide-mouth Nalgene bottle (easy to clean and therefore less likely to become trash, also great as a hot-bottle in winter).

2. I've been carrying a tiny Victorinox classic SD on my keychain ever since I've started hiking. At some point when I lost it, and while they're not expensive (though there are much cheaper options that also feel cheap), they also don't break, so I went to ebay, scanned the completed listings to get an idea of the lowest price I can get, and there I saw soooo many used branded victorinox (in great condition). None of them that I can remember had the logo/name of a tech company, which is a shame, because it seems like at so many conference booths they would aim for quantity rather than quality, whereas myself and most of the people I value, would rather appreciate something that is very very good in its category rather than assortment of junk that I wouldn't choose for myself even if I was stressed to buy a product in that category.

Not really "swag" but I would say iPod socks. I still have one that I keep an altoids tin inside of for transporting small fragile components.

Oh boy I can imagine exactly what you mean. I used to have a green/lime one.

Maybe St. Peter's bones?

I once got a pet rock.