Mine is The Last Trick of Dr Jacob Daley.
I've probably performed it close to a thousand times (no exaggeration) in the past 12 years. If asked to "do a trick" then 9+ times out of 10 that's the trick I'll do.
Four cards from the deck is less intimidating than 54 (I keep my Jokers) for a first trick with strangers, and easier to follow I feel.
I can do the actions in my sleep. But I vary the pace and some in-line joking depending on my audience; as well as potentially 2 follow-up phases depending on how attentive/interested they are. [When I was tending bar a few years ago for a couple of years, I encountered a large variation in attention spans you know!]
So for me, it's simple to execute, and becomes all about my performance and inter-play with whomever I'm performing for. Perfect! =)