Australia: Vegemite and Tim Tams (how original, I know). Friends love the Tim Tams and are probably equally pleased that I didn't give them the Vegemite instead.
Mersyndol (Paracetamol/Acetamenophen, codeine, doxylamine succinate) - great for sleeping on flights.
Bonds T shirts.
UK: McVities Chocolate Digestives.
Germany: Gummi Bears (from Bären Treff -
www.baeren-treff.de ). Normally I'm not that big a sweet tooth (despite the Tim Tams and Choc Digestives) but these are really, really good.