Maybe I'm a bigger racer fan than most here, but I enjoyed reading and watching what you all posted. You all know I like to do my top lists. So here's...
Ex's top 12 retro racers:
Battle Cars (1993 | SNES) = This is a vehicular combat racer released exclusively in the US by Namco. It resembles F-Zero with its use of Mode 7, but with weapons and a post-apocalyptic setting. The player can upgrade their car and weapons, and it also has a two-player simultaneous competitive mode.
F-Zero (series) = I'm gonna cheat and list the entire series as one entry. I've beaten every game in this series. Top highlights for me are F-Zero, F-Zero X, and F-Zero GX. All of those offer similar yet unique experiences within the franchise. At any rate, this series represents the very best in video game racing there ever was.
HSX HyperSonic.Xtreme (2003 | PS2) = A very much ignored futuristic racer. If you enjoy loopy twisty insane tracks, HSX is the game to play. It's also very challenging later on. Sadly reviewers shit all over this game, probably because it was too hard for their pathetic asses.
Kinetica (2001 | PS2) = A racing game set in the distant future, where racers compete on both Earth and outer worlds while wearing Kinetic Suits. These Kinetic Suits have wheels on the hands and feet, which racers can bring together in one wheel, or break apart in order to do aerial tricks. The Kinetic Suits are also capable of scaling walls and ceilings, allowing for some courses with varying elevations and orientations. Kinetica was the first game to use SCE Studio Santa Monica's Kinetica engine, which went on to power such PS2 titles as Twisted Metal: Black, WipeOut Fusion, SOCOM, God of War, Jak and Daxter: The Precursor Legacy, Ratchet and Clank, and Sly Cooper and the Thievius Raccoonus.
Mario Kart (series) = I'm cheating again, but fair enough. When it comes to kart racing, no other knock off even comes close to the quality of this franchise. I've beaten every single game in this series, even the arcade version. Highlights for me are Mario Kart 64, Mario Kart DS, and Mario Kart 7. I'd say ultimately Mario Kart DS is the absolutely pinnacle, it's unbelievably polished and just feels perfect to play.
Moto Roader II (1991 | TG16) = This is a top-down view combat racer. Unlike its predecessor, this sequel is set in a science fiction/future setting. Players can upgrade their car/hovercraft/tank in various ways, including better engines and combat weaponry.
Quantum Redshift (2002 | Xbox) = A futuristic racer similar to the Wipeout franchise. It has wildly varying tracks, with a strong emphasis on combat. A strong plot makes the gameplay feel more meaningful. The tracks themselves are open and are played in both forward and reverse directions. Each track has multiple routes which are discovered as the player unlocks the faster speed classes. The game retains a consistent 60fps, features 5.1 audio, and supports single and local split-screen multiplayer with up to four players.
R4 Ridge Racer Type 4 (1999 | PS1) = Great graphics, fun courses, super tight control, responsive physics, and a two player split-screen mode makes this my favorite series entry.
Ray Tracers (1997 | PS1) = This is an arcade racer where you have to crash into others cars to destroy them. It is a spiritual successor to Chase H.Q. I enjoy this more than Burnout.
Rollcage Stage II (2000 | PS1 & PC) = Brilliant racer with combat and the ability to flip your car upside down and keep on driving. This unique mechanic is implemented by stage designs that allow position exploitation in doing so.
SkyRoads (1993 | DOS) = This is a remake of the game Kosmonaut. It's a racer set on ten different stages ranging from the sun to the fictional world of Druidia. The goal is to get to the end of the level by jumping from platform to platform without crashing, running out of oxygen, running of of fuel, or falling off of the track. So you're more or less racing against your own limited dwindling resources. The OST is rather good.
Uchuu Race: Astro Go! Go! (1994 | SFC) = This is a Mode 7 enhanced racer from KAZe and Meldac that is similar to F-Zero. The courses tend to be filled with obstacles and tricks, such as currents that carry the player in one direction, or jumps over empty space. Colorful and fun graphics make playing a joy. This game was planned for a US release to be entitled Freeway Flyboys, but was canceled mid-development.