Flavors around the World:
Austria: Smarties, Kit Kat, Milka Cherry
Australia: Oreo, M&M's and Crunchie. (previous flavours: Nestlé Milo, Wonka Nerds, Creme Egg, Peters Drumstick, Berry Blast (Oreo and berry topping))
Argentina: In Argentina McFlurry was called McSwing but now they've changed to Mcflurry, they're sold in Oreo, Rocklets (they're far more popular than M&M's in Argentina) and Cadbury's chocolate and Cadbury chocolate and yoghurt.
Brazil: Oreo and M&M's
Canada: McFlurries are sold in Oreo, Smarties, and Strawberry Shortcake varieties. Various times of the year a Rolo or Caramilk McFlurry is available.
France: M&M's, Daim, and Crunch Almond varieties
Germany: Smarties, Kit Kat, Milka Cherry
Greece: Nestle Crunch, Nesquick, Smarties
Hong Kong: Oreo, Smarties, and Cappucino are available.
Malaysia: Oreo, M&M's
Malta: Cadbury Flake Deluxe (available since summer 2006), D'aim, Kit Kat, M&Ms and Smarties
Mexico: M&M's, Oreo, Butterfinger and Crunch are the flavors available
Netherlands: M&M's (peanut), Nestle Crunch, Rolo
Norway: Non Stop, Daim and Oboy available
Pakistan: Buttercrunch and Oreo.
The Philippines: M&M's and Oreo.
Singapore: Oreos and Cappuccino are the two flavours available
Spain: M&M's, Smarties and Nestlé_Crunch.
The United Kingdom: Smarties, Crunchie pieces & Dairy Milk pieces. At Easter, a Cadbury Creme Egg McFlurry is sold (also available in Canada), which has chocolate pieces with yellow fondant icing. In the last year, there have been Dream (white chocolate and strawberry sauce), Lion bar (toffee and wafer) Yorkie (milk chocolate and chocolate sauce) and currently Flake Deluxe (milk chocolate and chocolate sauce)
The United States: M&M's are used in place of Smarties, and Strawberry Shortcake is now unavailable though it was sold in various markets. A greater variety of flavours were to be had in the past, but most have since been removed, perhaps due to insufficient demand.
Uruguay: In Uruguay McFlurry was also called McSwing but now they've changed to Mcflurry, they're sold in Oreo, M&M's, and Dulce de leche (Caramel) .
I'd love to try the Dulce de Leche, but we dont have that here.

But Oreo & Butterfinger Crunch ones are dope.