Teams: Forza, Allez, Amunt
As far as I know, Canon and Nikon are the most respected brands. This is probably because digital photography is still very young, and these two companies already had a reputation for excellence before the digital market appeared.
What's most important is a bit like asking what's most important in life? It depends on you, and you'll only know once you've experienced a bit of good and bad alike. When people ask for advice when buying a computer it's a very simple answer: get the fastest one. There's no such thing in cameras, no one quality, there's a long list of attributes you have to consider.
La Juve? Lasciamo perdere.