I am a coffee freak and I love Cappuccino. I want to know what exactly is the Original Cappuccino. What portion of milk, water and coffee does it contains? And is cappuccino with more foam as good or with less foam?
It's made from 3 equal parts
Milk foam (top)
Steamed milk (middle)
as illustrated (bottom left) on this image designed by Lokesh Dhakar...
There is also some details here, however it does not describe the important split in foam and steamed milk.
For a 3-ounce macchiato, use a 2:1 ratio of espresso to milk; for a 6-ounce cappuccino, 1:2; and for an 8-or-more-ounce latte, 1:3+.
As to the second art of your question, a cappuccino with more or less milk would not be a cappuccino by definition. However would it taste better, that's down to your personal taste and how much you like foam. Personally for me, it would become more a desert ;)
The original cappuccino was an 18th century Austrian drink Kapuziner, so named because the addition of cream made the coffee the colour of Capuchin monks' robes:
Kapuziner: Kaffee, ein Kaffee mit Sahne, Zucker, Gewürz und drey Eidottern aufgesodst.
[... a coffee with cream, sugar, spices and three egg yolks...]
Kapuziner (Kaffee mit wenig Obers oder Nidel, wie wir sagen)
[... coffee with little cream...]
- Der Schweizer Schützenfahrt (1868)
Similar drinks are sometimes still sold under the name Viennese coffee.
From the 19th century in Italy we see cappucino as:
Cappuccino: caffè nero con poche gocce di latte o panna che gli dànno il colore della tonaca dei cappuccini e e da ciò prende il nome.**
[black coffee with a few drops of milk or cream which gives it the colour the tunic of the Capuchins, from which it takes it name]
Over time this has evolved into the modern version of the drink, usually served in a medium sized cup in equal parts espresso, steamed milk, and milk foam.