I agree with Brett, there's no "best" trick that suits all of us - tricks have to fit to your style of performance, your favourite type of magic, your experience, your confidence, etc. That being said, I think Breakthrough by the Mengel Brothers is one of the more one size fits all tricks. Easy but effective enough for all levels of magicians, and can be incorporated into a lot of styles of routines since it uses such common items. It is a bit pricey though.
Coin Under Watch by Oz Pearlman is one that I love too, but it might not be everyone's cup of tea. I'm only recommending it because the instant download is on sale on penguinmagic for 75% off I think. It gives a nice base for some effective coin routines and vanishes, though the most effective routines require some bold sleights. T11 has some nice free coin downloads too, if you're into coin magic.
I'm more of a Jason England guy myself. I have these downloads:
The Bottom Deal by Jason England
Push Through Shuffle by Jason England
Double Lift by Jason England
Push Off Second Deal by Jason England
Multiple Shift by Jason England
Tabled Faro Shuffleby Jason England
Gambler's Cop by Jason England
Hermann Pass by Jason England
Side-Steal by Jason England
Center-Deal by Jason England
Zarrow Shuffle by Jason England
Classic Passby Jason England
MacMillan Switch by Jason England
Diagonal Palm Shift by Jason England
Single Card Straddle Pass by Jason England
Top Card Cover Pass by Jason England
Slipshot Chris Kenner
Pop Out Chris Kenner
SWE Shift Chris Kenner
Let me tell you that it is obvious why these guys are extolled for being the best in the field. Jason England's smooth handling of the cards leaves me wanting to watch each of these downloads over and over. Even if you think you know everything about the move you will always find something that you missed. But as mentioned in a previous comment it really depends on what you are looking for. Try one of Jason England's Downloads right here off of Theory11.com. If I could recommend one it would have to be the Classic Pass, he does a terrific job of teaching the move. It's not going to break the bank and you will have a handy tool up you sleeve for bringing a chosen card to the top of the deck.