I don't really have a favourite card per say in MTG but there a bunch I enjoy.
I'm playing a green-red burn+fight deck
I like dragons, i think they're cool. So I use scaleguard sentinals to defend myself with burn spells as I use typical green cards to boost my mana, and then I come out swinging with my big dragons like foe razor.

It's not the best deck, but it's fun!

Draconic+Roar+%5BDTK%5D.jpg
Here are a few cards I have in my deck.