what is the best driving game?

If it's flight you want this are my biggest recommendations.

[Realistic Gameplay/Simulator -- X-Plane]
X-Plane is a flight simulator produced by Laminar Research. A desktop version is available for Mac OS X, Windows, and Linux, while a mobile version is available for Android, iOS, and webOS.[1] X-Plane is packaged with several commercial, military, and other aircraft, as well as basic global scenery which covers most of the Earth. X-Plane also ships with other software to build and customize aircraft and scenery. X-Plane also has a plugin architecture that allows users to create their own modules, extending the functionality of the software by letting users create their own worlds or replicas of places on Earth.
As of February 2016, the most recent version is X-Plane 10.45. X-Plane 10 comes in a cardstock or tin case on eight dual-layer DVDs, most of which comprise the global scenery, which is 86 GB compressed. The scenery spans from 70 degrees south to 74 degrees north. Switching the planetary model to Mars is an option that comes with X-Plane 9 only, and although the atmosphere is thin, flight is possible.

[Realistic Gameplay/Combat -- IL-2 Sturmovik: Cliffs of Dover ]
IL-2 Sturmovik: Cliffs of Dover is a World War II combat flight simulator developed by the Russian software house 1C:Maddox Games. It inherits the name IL-2 Sturmovik from the Il-2 Sturmovik classical series (2001-2009) and is considered as being a part of the series, but it runs its own game engine instead of sharing it with the classic series.
IF YOU CANNOT GET THIS GAME TO RUN OR IF IT IS VERY BUGGED, PLEASE VISIT THE ATAG WEBSITE.
Grab the TEAM FUSION patches at teamfusion.theairtacticalassaultgroup.com

[Arcade -- FLYING TIGERS: SHADOWS OVER CHINA]
FLYING TIGERS: SHADOWS OVER CHINA is an air-combat action game based on the historical events of America’s secret volunteer squadrons that flew against Japan in the China-Burma-India (CBI) Theatre of WW2.
Get ready to swoop the skies of Asia as FLYING TIGERS: SHADOWS OVER CHINA reawakens a diverse set of historical WW2 air-battles, including the Japanese Christmas-raids on Rangoon in 1941, the Flying Tigers’ first combat over Kunming in China, the Battle of the Salween Gorge, “Hump” escort missions over the Himalayas, the Invasion of Malaya, and the Japanese conquest of Burma, to name a few.

Runner Up -- Flight Simulator X
Though it was considered as the best simulator in the past, sadly Microsoft abandoned further update of this game.

Need for speed.

My personal favorite is Forza Motorsport 6. Very realistic cars and tracks. and you dont have to know alot about cars to have fun tuning cars, it will tell you how much it will upgrade that area by.

In terms of realism it's the gran tourismo series.

In terms of arcade fun I like Mario kart 64.

For aircraft driving it's probably flight simulator.

All Stars Racing transformed. I think.