Huge flavor fan here, more interested in the story than the game. I use my decks both to beat my opponents down (after all, this is a dueling game) and as inspiration for the planeswalkers I create to go with my decks (for example, Doon Verai is a Dimir agent-turned-planeswalker whose deck is all about milling the bjeezes out of everything).
I've been playing for quite some time (since 2002) though I took a brief hiatus during Kamigawa.
My favorite Magic card is: Favorite card? Not sure. I've got a few favorite characters: