In my industry (High-Tech) I admire the following people (short list)
Steve Jobs CEO at apple -> For being a visionary and changing the world
Guy Kawasaki CEO at Garage -> For being a damn good speaker and a very pragmatic guy
Steven Wozniak (Designer of the Apple II) -> For being one of the smartest engineers of his generation
Ivan Sutherland -> For having created sketchpad, a program which was technically very impressive for his time
Paul Lutus -> For having written one of the best selling word processor, Apple Writer (for the Apple II) out from a Cottage in the middle of nowhere
Charles Simonyi -> For being an awesome programmer, who started as a starving student (he`s an immigrant from Hungary), he then worked at Xerox PARC, then Microsoft (the father of the revenue bomb strategies in the 80`s) and he recently went to space. The American dream is apparently not a feary tale
This list could be 4 pages long but will stop here for not polluting this thread too much 
Not too sure about business idol but I do admire great speakers. Therefore, my list is:
Ken Blanchard - fantastic storyteller
Jack Welch - terrific and inspirational leader
Marcus Buckingham - love his strengths based views
Andrew
I`m another individual that doesn`t really idolize anyone. I would definately have to give props to Bill Gates for bringing the internet to what it is today!
I really admire this site also, it brings me alot of inspiration 
My idols are the key to my success after reading 2 or 3 good books on them, they inspired me and gave me an entire new look on how to approach being a business. My idols are:
Richard Branson - You don`t have to ask why he is one, just take a look at the business empire he has built from nothing!
Duncan Bannatyne - I admire everything about him and his businesses, he was brought into the World in Poverty, and had a vision although poor - he worked as hard as he could to build his empire.