For a detailed pas habaa bkisnin discussion see here.

I. Varieties and circumstances that warrant a Birchas Hamotzi:

Pizza:
Three slices of 18″ pizza pie
Three slices of 16″ pizza pie
1/2 of a 14″ thin crust pie,
1/2 of a 12″ regular pizza pie
1/2 of a 9″ deep dish pizza pie

Other:
Bagel chips made from bagels
Calzone – 1 from a pizza shop; 2 pre-packaged frozen
Croissants (when augmenting a dinner meal)
Croutons (toasted)
Matzos (Sefardim should ask their Rabbi)
Melba toast
Mezonos rolls – that taste like cake and are augmenting a dinner meal, and those that taste like bread
Soft pretzels (when augmenting a dinner meal)
Stromboli – 1 from a pizza shop; 2 pre-packaged frozen

II. Varieties and circumstances that warrant a Birchas Mezonos when eaten as a snack:

Bagel Chips
Breadsticks
Croissants (as a pastry)
Flatbreads (all varieties)
Hard Pretzels
Kichel
Matza Tams
One slice of pizza
Pancakes
Pita chips (toasted)
Soft pretzels
Ryvita
Tam Tams
Wheat Tams

III. Varieties that warrant a Birchas Mezonos under all conditions:

Bagel chips (fried)
Blintzes
Croutons (fried)
Doughnuts
Noodles
Pita chips (fried)