Most significant contributions...

[Chad Stewarthill]

5. Frank Williams
4. Ron Dennis/John Barnard/Mclaren MP4/4 (I know, I know)
3. Ayrton Senna da Silva
2. Professor Sid Watkins
1. Jackie Stewart

 

[tonyw151]

Brilliant lists guys, though one thing that makes Colin Chapman much more important in my eyes is when he took cash to change the colour of his Lotus 49s. Changing the game for all.

 

[siffert_fan]

Colin Chapman: advanced F1 chassis design more than anyone else.

Mike Costin and Keith Duckworth: created Cosworth and the DFV engine that led to the most entertaining (at least to me) era that Formula 1 has ever seen.

Jim Clark: For showing that being the most talented driver in the world doesn't mean you have to be an egomaniac. Lots of today's drivers should absorb that lesson!

Sir Jackie Stewart and Sid Watkins for all of the reasons given in earlier posts.

 

[Il_leone]

Contributors
Colin Chapman - innovation was his key to success
Jackie Stewart - he pursued professionalism in that drivers should be paid well for taking risks in an F1 car and also increase safety for them as well
Bernie - love him or hate him F1 is what it is because of him
Senna - immortalised through his tragic accident. The ultimate F1 modern day driver and no racing driver has received such iconic status in the sport
Senna/Prost - took teammate and championship rivalry to a new level of intensity and ferocity
The one that people have forgotten
Ferrari - been in the sport since the beginning although they have had their ugly moments as well

 

[siffert_fan]

I should add to my list:

Rob Walker- who proved that a small team of smart, enthusiastic and talented privateers could compete with the factories and, IMHO, thereby encouraged others such as Jack Brabham, Bruce McLaren, Lord Hesketh, Frank Williams and others to form their own teams. The sport would be much the poorer if Mr. Walker hadn't graced it with his presence and wit (and Stirling Moss).

 

[Bill Boddy]

Double like.

 

[MCLS]

Most of the ones I would pick have already been chosen so I'll add two of my own

Herman Tilke - Love him or hate him, his tracks have played a part in the modernisation of F1 in the 21st century and quite a few of his tracks have been quite successful as well, and in reality, most of the qualms people have with his circuit designs are things that are out of his control such as circuit width and run off areas as they are put in force by the FIA and also circuit locations in countries which shouldn't really be hosting F1 races

Imola 1994 - a really sad inclusion, but that weekend changed the face of modern F1, safety features and track 'sanitisation' following the deaths of Ratzenberger and Senna and that led to what we see today, Kubica walking away from Canada 2007 and only missing one race, Webber flying upside down at Valencia in 2010 and walking away completely unharmed, while it'll never be completely safe, Imola 1994 quickened up the pace of the implementation of safety measures to the cars and drivers

 

[Mephistopheles]

Murray Walker, although I did watch an old British GP today where he was commentating and he said, "The car is completely undamaged other than the car itself...."