Karrell Fox and Aldo Colombini for their creativity, humor, approach to magic and approachability. Both were very easy to talk to.

David Copperfield, watching him in my teenage years got me into Magic.

After that, Derren Brown, James Randi and Houdini.

Also David Blaine.

They all have their strengths and weaknesses but I love them all...

Because there ought to be at least one female in this list; and because she richly deserves to be included:

Frances Ireland Marshall (March 25, 1910 - May 26, 2002) -- an accomplished magicienne, specializing in children's shows; author of several books including the classic memoir "You Don't Have To Be Crazy - But It Helps."

I never saw her perform solo, but she was a frequent asset in others' shows as a truly "lovely assistant," spooling paper serpentines from her mouth and otherwise helping to make the magic happen. She gave me the teenagers' discount on many OTC tricks and gimmicks at the Ireland store on Dearborn in Chicago back in the day, and once she even invited me to attend an after-hours gathering where locals and out-of-towners would demo their latest effects to colleagues in the magic community. I had a boyish crush on her and remember her fondly still after ca. 65 years.

I’d have to say Goldfinger and dove . I wasn’t into Magic until I saw them perform, they brought some thing to Magic. No one else had done before rhythm.

Doug Henning, for fostering my childhood love of magic.

Penn & Teller, for reacquainting me with magic as an adult.

Ted Annemann for helping me explore the far depths of magic once I got back into it as an adult.

And Eugene Burger for keeping me sane while digging deeply into said magic.

I'd say I owe them all a lot.

Dick Oslund. No question about it. He found me on here about a decade ago and we became instant friends. He helped me in more ways than just magic. He was a friend. He was one of a kind. I miss the hell out of him.

Max Malini - as a magician and showman. He did everything right! He understood what commercial magic is and why it works! Every trick he performed was a hit in itself! He used his charisma and the power of his voice to break into the personal space of the crowd and after he left, people continued to discuss what they had seen. He is a genius of magic!
And of course I admire the people below this message! Each of them is unique!

James Randi!

He is one of my 3 modern day heroes (James Randi, George Carlin, and Jacques Cousteau)of which I met Randi and Carlin.

Well, as I'm an old man;

Mark Wilson

He was the first full fledged magician I ever saw. I parked my butt down in front of the TV for "The Magic Land of Alakazam" every week.

Definitely Harry Lorayne, for his way of teaching, always describing everything in details, his philosophy to work impromptu from borrowed decks, and his performance energy.
My only regret is that I learned about him much too late to see him perform other than in videos (he was already 90 or so).

And also the French mentalist Fabien Olicard!
I don't perform mentalism myself (more into cards) but I saw him several times in live performance and always enjoyed it, this is also thanks to him that I first learned about memory systems (from which further research lead me into Harry's memory work, then into his magic work).

I liked Harry Lorayne's work so much I even sought out a copy of his board game!

That's very cool!
Certainly something I could have bought too (just checked some photos on eBay, but the $25 to $35 shipping fees to France are kinda prohibitive)

I would also add... my uncle; Robert "Bob" O'Neill. He was the first person I saw do magic live and in person. (In my living room, no less) He also got me my first magic kit. (An Adams Kit, with Chinese Rice Bowls, and a "balancing" wand.) I don't think he's alive now, I can't find any reference to him in the internet. Unfortunately, "Robert O'Neill" is a very common name.