1. Diddy Kong Racing (Nintendo64)
This game is very fun and unique for its time. One of the coolest things about this game is it actually contained an adventure mode. This was actually the first racing game to have a free roaming adventure mode. Two years later the game Crash Team Racing would steal this aspect from Diddy Kong Racing. This game was also unique due to the fact that you had 3 vehicles you could use a cart (very standard vehicle), hover craft(very slippery controls due to lack of any traction), and Planes (used to fly high in the sky and reach special areas, however they are very slow.) Add in an all star cast of wacky Rare characters (highlights are Banjo, Conker, and Diddy Kong) This game had about 50 tracks of fun, and had some strategy due to the fact that getting 2 or 3 of the same item in a row uprgades it. As you can see this game revolutionized the Racing genre and still holds up to this day.
2. Crash Team Racing (Playstation 1)
As stated above, Crash Team Racing copies the adventure mode from Diddy Kong Racing, but due to the pure hectic action of this game, it is actually better than its predecessor. This game combined 2 of the best racing franchises and added its own twist. Many of the tracks are total rip offs of mario kart 64 (including piranha plants on the level Papu's Pyramids and Coco Park is the exact same as Luigi Circuit),the adventure mode really is a complete rip from Diddy Kong Racing, even the map appears to be the exact same. However, this racing game is very simple, the tracks are generally short but the use of items makes up for it. For example, when playing an average match of this game, missiles will be locked onto you, you have to dodge lab test tubes (that make you spin out like Mario Kart's bananas) and to top it all off you hit a tnt block. TNT blocks will sit on your head and count down from 3-0, the only way to stop this item from exploding is by rapidly tapping the R1 button. As you can see the matches can get very hectic in this racer. Add in bonus challenges and some awesome Crash Bandicoot music, and you have a pretty awesome racing experience.
3.Sonic Racing (Saturn, PC, Gamecube)
Sonic Racing is a very unique game. It is the most simple game on this list due to the fact that there is no adventure mode and no items. But these abscences do not stop this game from shining. This game has a very arcadey feel to it, you select your racer(s) select a cup than your all set to race. During the race you simply run through the levels, jumping over obstacles and try your best to stay close to the track. By collecting enough rings on the track you can use launchpads on the ground,or open passageways that cut through the track. Sometimes these passageways even contain a Chaos emerald (one hidden on each track). This games main selling point is the variety. For example, the characters are vastly different, some are really slow but can shoot projectiles, while others have the ability to walk on water, glide, fly etc. Through use of these abilities you can explore your limitless environment. Thats right, the environments are full blown, so you cant "fall off the track" like mario kart and have to wait to get picked up. In this game, if you fall off the track into the water you have to wade through that water till you find land, sometimes crossing what seems like "off limit areas" actually uncovers secrets. This game even features unlockable characters which adds alot of replay value to an arcadey game like this. My only gripe about this game is the music was done by a Pop Star and while some of the tunes are quite catchy, it just doesnt feel like sonic music and doesnt fit the feel of the game very well.