Wow, that's a toughy. I'd have to say there is a many-way tie. Anton Zeilinger, Erwin Schrodinger, Heisinberg, Plank, and that one dude with the wicked hair..... something like Albertos Instine?!?.....Whatever he's known for.
Ed Witten is my favorite living physicist, because I am a huge fan of M-Theory, and it wouldn't exist without him. Of course, Michio Kaku, and many others have made significant contributions as well, but the parts that particularly fascinate me - such as Duality and the unification of all of the string theories into the M-Theory - were most strongly influenced by Witten's work (IIRC, Witten invented Duality practically single-handedly, and he was the one that made some of the first mathematical applications of Duality to the unification of the string theories).
Albert Einstein, his work in physics, his philosophy, and the way he changed it.
Sure all of the above are great physicist but your forgetting the greatest of them all ! The GREATEST physicist was Paul Dirac. Some of his many achievements are listed below
1) Formalised the mathematics of quantum mechanics
2) Joined special relativity and quantum mechanics together
3) Gave birth to quantum field theory
4) First to predict that positrons existed even before their experimental discovery
5) Gave a symmetrical form to electromagnetism to take into account the possibility of magnetic charges
These are only a few of his achievements. Indeed Paul Dirac was the greatest physicist ever!
Benjamin Franklin, because he
made an important contribution
without actually being a physicist
strictly speaking, and:
Michael Faraday, because he made
what I consider the important
discoveries about electromagnetism
the first transducer for turning
work into electricity, and the
first transducer for turning
electricity into work.
Dirac, that is a good one - his contributions are often overlooked outside of the Physics community - the ket-bra formalism is one of the most beautiful I know of. I like its liquidity, the way it can be chenged from an abstract algebra to a discrete rep, then to a continuous rep, then back - very nice. Personally I like them all, even all the little known researchers and people who wrote practical how-to books that did little to change the history of physics but did a lot to sharpen people's abilities. The only one I don't like is Heisenberg - because he was a Nazi.
Einstein, I love his genious, humility and wit.
Newton, it's just amazing what he did.
Tesla, underrated genious.
Dr Abdus Salam [ Pakistan ]
My favorate Physicist is Late Dr Abdus Salam. He did alot for Pakistan but was always treated badly because he was an Ahmadi Muslim by faith and Ahmadi Sect has been declared non-Muslim in Pakistan in 1974 by the then National Assembly. He is the first Muslim and the only Pakistani Nobel Laureate
He got his Nobel Prize in 1979. Members can visit the following links:
Dunno if he was actually a physicist but i personally think that Ernest Rutherford was a pretty cool guy! He experimented and explained the basic structure of the atoms we know today which i think is groovy.. however i like Tesla too cos of his outrageous claims...what a pro!
Now, I know he is not a physicist, but Charles Darwin certainly deserves to be mentioned in the same breath as the great physicists. The Thoery of Evolution is one of the most profound theories ever devised by man.
As for physicists, Galileo is my pick, not so much because of what he discovered, but the social environment in which he discovered it.
Einstein comes a close second because of the sheer breadth of his influence over the whole of physics.
He wrote the BEST physics book I've ever read. His book is the main reason I got interested in physics. "Black Holes and Time Warps" It's not as technical as something by Greene or Kaku, but still very informative. I also think that some of his work on gravity wave detectors like LIGO is going to change the way we view the Universe. Plus he actually returned an email I sent him. I'm sort of suprised no one said Hawking, 5 years ago he would have gotten votes. Hawking radiation and black holes evaporating is a pretty cool theory you got to admit.
edit- whoops sorry just saw someone did say Hawking, my bad.