I'm with tealily,
I have a large number of decks that are used for various things and I love them all for different reasons
My 'goes everywhere with me' deck is Legacy of the Divine but it's not my all time favourite, it just fits nicely in my bag.
If I was only allowed one deck for the rest of my life (ok, I'm freaking out at that thought), it would be Deviant Moon.

No, wait, Bohemian Gothic.

Scratch that, Darkana.

Nope nope.......erm erm......

See what I mean