Probably my favourite gimmicked deck (if I am going to use one) would be the Gobsmack Pack by Richard Sanders.
It's an amazing effect and easy to perform! I think he described how to make one on one of his DVDs (though I can't remember which one!).
The basic effect is that you spread the cards face up between your hands or on the table. The audience can see all the faces and that they're all different. There is one face down card in the pack though - you call this your 'mystery card'. I usually ask someone if they know what it is. When they say 'no' I say 'that's why it's a mystery' - works every time!
Anyway, you have a spectator merely think of one of the face up cards (no force!). You close the deck up and they name their card - say it's the 5 of spades. You say you're now going to reveal the mystery card and they won't believe it... You spread through the face down pack to reveal the single face up card - it's the 2 of hearts! (?) You seem amazed - they seem confused. 'Amazing, isn't it?' I usually say, as a pull the card out of the pack to reveal that the card has 'I know you will think of the 5 of spades' written on it!
Instant reset - different card every time - easy to make - easier to perform - killer reactions! I cannot recommend this strongly enough.
