Going back to my first foreign venture as a child (Holland) in no particular order

EUROPE
UK (all + Jersey & Guernsey)
Holland
France
Belgium
Luxembourg
Andorra
Spain
Portugal
Greece
Romania
Czech Republic
Former Yugoslavia
Former East Germany
Former West Germany
Denmark
Norway
Sweden
Irish Republic

ASIA
Singapore
Indonesia
Malaysia
Thailand
Philippines

Americas
Canada
USA
Mexico

I think thats about it I've not counted airport stops/plane changes (Bahrain, Hong Kong, Pakistan) only places I've at least overnighted in