I agree with Jo - wear what you're used to wearing (unless you're Liz Taylor). Lots of jewelry has been left behind, or in order to avoid that fate, rinsed down the drain. 8-( I see people wearing what I'm generally used to seeing here. Some diamonds, etc., but nothing head-turning (in a gaudy, bad way).
I usually bring 2 pairs of earrings - one gold, one silver/white gold. Usually hoops. If they are precious to me, I make sure I can buy a replacement in case something happens. The other pair goes into the money belt (very flat).
I don't wear necklaces; I carry a backpack, and I've nearly broken a chain a few times getting my pack on. I don't wear any rings when I travel anymore; I've had problems with my hands swelling, so nothing gets lost those first few days when I can't get any rings on. I CAN'T get my wedding ring off...I'm stuck with that LOL!