I have heard a legend that the highest-paid entertainer prior to the
modern rock era was the San Francisco City Organist sometime between 
1900-1940.  According to this legend, he was paid the then-incredible sum
of $110,000 a year.  He played three shows a night and was the origin
of the saying "they were lined up around the block" as indeed people
would line up around the block where the theatre was, in order to hear
this guy play the theatre pipe organ.  --Can you supply his name and
additional information?  Thanks!

Well, after writing about George Wright in the comments section, I
read the question again and realized you were asking about an official
"city organist" rather than about an organist who simply played in the
city.  I'm glad I did misread it the first time or I would never have
had the pleasure of writing what I did in the comments section.

However, the man you are looking for is Edwin Lemare.  He first played
the organ at the 1915 Panama Pacific International Exposition.  The
organ he played was built by the Austin Organ Company of Hartford,
Connecticut.  It has a four-manual console, 7,500 pipes and 117 ranks.
I use the word "has" instead of "had" for the simple reason the organ
still exists, though now in storage. In early 2003 a climatic
dedication ceremony and concert will mark a political and financial
struggle by San Franciscans to bring their 40-ton technological
masterpiece back into municipal service.

There were organ recitals every day of the fair and they were played
by some of the best in the world.  But the crowds favorite was Edwin
Lamare from England.  He was so popular, they had to add to the organ
concert hall's seating capacity.

He gave recitals twice a day and had a different repertoire for every
one of them.  By the end of the fair, he had given 121 concerts heard
by a combined audience of over 150,000 people.

His even being there was an amazing story in its own right.  His
contract with the Exposition Company forced him to leave his pregnant
wife behind in Liverpool just days before the birth of his daughter. 
In the midst of the First World War, Lemare crossed a U-boat infested
Atlantic to arrive in America.

 Lemare's first concert was heard by only 400 people. Attendance
exploded once word spread that the greatest living organist was
performing and the concerts were sold-out. The front rows were filled
with organists who paid the 50-cent admission to the fairgrounds just
to hear Lemare play. His wife, son and new baby daughter soon joined
him in San Francisco.

When the fair closed, the City of San Francisco took possession of the
organ and had it reinstalled at the Exposition Auditorium.

Lemare was then hired by the City as municipal organist to perform two
concerts weekly.  He was the highest paid organist in the world. 
However, his salary was $10,000 rather than the $110,000 you mentioned
in your question.  In fact, his pay was so high that the San Francisco
supervisors voted to reduce his salary by 60%.  He played his 190th,
and last, concert, June 1921.  Feeling rejected by the city he loved,
Lemare accepted a position as the municipal organist for Portland,
Maine and, later, Chattanooga, Tennessee. He eventually retired in
Hollywood, California.

His most famous composition was "Moonlight and Roses" which was
adapted from an Andantino for organ.

Edwin Lemare died in 1934

Thanks to your question, I have now had the pleasure of writing about
two of the world's great musical artists.

Websites used as sources for the above:

"xrefer - Lemare, Edwin (Henry) (Ventnor, IoW., 1865 - Los Angeles,
1934" - From Oxford Dictionary of Music - (
http://www.xrefer.com/entry/241909 )

"Waterfront Pavilion - Project Description" - From Waterfront Pavilion
Project
( http://www.sfpavilion.org/organ/ )

"Behind The Velvet Curtain" - From Vic Ferrer Productions
( http://www.vicferrerproductions.com/story.html )

Search - Google
Terms - san francisco city organist, san francisco exposition +of
1915, edwin lemare

If you need any clarifications before rating the answer, please ask.

Cheers
digsalot

That's it!  Just superb!

I am posting this in comments because there are no links or references
to make it an official answer.  Just remarkable personal memories of a
wonderful man.

There is only one person you could be thinking about and he did not
play between 1900 and 1940.  He began playing in San Francisco in
1940.  I have had the pleasure of hearing him several times, had the
privilage of calling him friend, and have been a guest at his home in
the Hollywood Hills more than once.  I am a pipe organ fanatic.

His name was George Wright and the organ was the Mighty Wurlitzer at
the 5000 seat Fox Theater in San Francisco.  He was there for four
years but only a few times did he do three shows a night.  The amount
of money he was paid then is in the realm of urban legend.  His
fortune came later in his career.

As for him being the origin of the saying "they were lined up around
the block," I don't really know, but they certainly were.

When I was 15 years old in 1960, I had my first experience hearing
George Wright.  I was visiting an aunt and uncle in Pebble Beach and
they had obtained tickets to an organ concert to take place at
midnight at the Fox Theater.  We drove to San Francisco and watched
the late movie.  I still remember its title.  It was "Sink the
Bismark."  At the time, I had no idea who George Wright was other than
as a friend of my aunt and uncle, and of course he played organ, big
deal!

We did not have to leave our seats after the movie as we already had
the concert tickets.  Outside the theater, almost 5000 people had
lined up waiting to hear him play.

That night has been written about by more than one pipe organ fan and
even though I had the privilage of being there, I am going to quote a
paragraph written by Allen White.  Mr. White was the producer of this
series of midnight concerts at the Fox Theater by George Wright who
had returned to the Fox after a 16 year absense.  The quoted paragraph
follows:

"Just after midnight, the house lights dimmed and what I will always
remember as a defining moment in my life began to unfold. From the
organ chambers located to the right, the left and above the stage,
came first the sounds of pipes recreating violins tuning up for a
concert. Then, 32-foot pipes literally shook the building with the
intensity of a decent-sized earthquake. From six floors above and a
full city block away, a piercing spotlight hit the orchestra pit, and
the sound of Irving Berlin's "There's No Business Like Show Business"
punctuated the night air. Slowly and with an awesome majesty George
Wright emerged, seated at the magnificent San Francisco Fox Mighty
Wurlitzer Theater Pipe Organ. "George Wright's Showtime" had come to
life." - Allen White

Later my uncle introduced me to George Wright after the concert.  I
not only became a die hard George Wright fan but a die hard pipe organ
fan period.

I have heard him play in Los Angeles, Chicago, and New York.  I have
heard him play at his home.  His house was atop the Hollywood Hills. 
As he claimed, he did not buy the house for the view but because it
was big enough to contain a full pipe organ.

He died in 1998.

In my opinion, he was the greatest American musician of the 20th
century.  I miss him.

George Wright may not be the man you are asking about, though I can
think of no other who might come close.

But I am glad you asked the question because I have had great pleasure
writing this though my view of the monitor screen has become somewhat
blurred.

digsalot

I am curious, was it Edwin Lemare, or George Wright you were looking
for?  I have also been where digsalot was in the 60s and I thought Mr.
Wright fit the description.

It was Edwin Lemare that I was looking for.  --wildcard-ga