These are some of the most
Purrari

The ever-unique Deadmau5, aka Joel Zimmerman, wrapped his Ferrari 458 Spyder with a Nyan Cat theme. The striking vehicle can be seen whizzing around Toronto, CA, often being used to bring other celebrities with Deadmau5 on his famous "coffee runs" as seen on YouTube. UPDATE: Ferrari actually forced Deadmau5 to REMOVE the wrap, and remove all purrari logos from the car! Hater's gonna hate.
Maybach Exelero

This car costs an astounding $8 million and only one was made for Jay-Z, showcasing his immense wealth. The car weighs over two and a half tons, but can still reach speeds of 218mph. The super polished interior rocks leather, aluminum, and carbon fiber accents.
Fisker Karma

Fisker Automotive produced the Karma, an electric powered luxury sedan, from 2011 to 2013. In that time they were able to get an impressive number of celebrities to purchase one, most notably Justin Bieber's chrome version. Other celebrities include Ice T (who called his a "Space Shuttle"), Leonardo DiCaprio, Taylor Lautner, Ashton Kutcher, Joe Jonas, Tommy Lee, Cee Lo Green, Al Gore, Phil Mickelson, and Julio Jones.
Bentley GT Continental

Paris Hilton is basically a real-life Barbie doll driving around in her bright pink Bentley GT Continental. The colorful car matches perfectly with the star's outgoing personality.
T-Rex

Rob Dyrdek owns a vehicle that is technically a motorcycle called the T-Rex, made by Campagna. It looks like a cool reverse tricycle combined with a sports car. This car fits in perfectly with Dyrdek's "Fantasy Factory" and there has been footage of the crew playing with it.
Lamborghini Aventador

Chris Brown is not as well known for his collection of Lamborghini's as he is for his music and his infamous relationship with Rihanna. However, he has a good eye for cars. He had his Lamborghini Aventador painted to match his Nike Air sneakers, but it was not the first Lambo of his to receive a interesting paint job.
Blastolene Special

This ridiculous vehicle, now owned by Jay Leno, has the engine of a M47 Patton Tank and weighs almost 5 tons! Yet, this is only about a tenth of the original weight of the tank. After Leno upgraded this monster, it produces around 1600 horsepower and looks much more awesome to match it's crazy engine.
Rolls Royce Phantom Drophead

The famous soccer (football) star David Beckham owns many cars, but one of his most famous was his Rolls Royce Phantom Drophead. He blacked it out and customized many of its features, even the hood ornament, but eventually sold it in 2012. He now owns another Rolls Royce, the Ghost.
Matte Black Collection

Justin Bieber has a thing for matte blacked-out cars. He has a Cadillac CTS-V, a Smart Car, a Range Rover, and a Mercedes Benz Sprinter Van all blacked-out. The kid seems like an evil villain collecting all of these cars.
Audi R8

Oh, I guess the kid isn't THAT evil. Bieber owns an Audi R8 that is covered in Leopard print. Perhaps after he owned the chrome Fisker Karma, he just had to one-up himself in the eyes of the media for weirdly painted cars.
Ferrari F430

Kim Kardashian owns TWO Rolls Royce Ghosts, showing up David Beckham, but her coolest car is her Ferrari 458 Italia. Interestingly enough, she got the car as a wedding gift for her short-lived marriage to Kris Humphries.
Bugatti Veyron

Many stars have elected to buy a version of the car "Top Gear" named 'Car of the Decade' for the 2000s. The Super Sport version of the Veyron became the fastest street legal sports car in the world, able to hit 267mph. The list of owners of various versions of the Veyron include Simon Cowell, Criss Angel, Jay-Z, Chris Brown, Birdman, Lil Wayne, T Pain, Xzibit, and Flo Rida who owns a bright pink one.
Lamborghini Aventador LP 700-4

Kim Kardashian bought Kanye this $750,000 Lamborghini Aventador for his 35th birthday. Perhaps she knows how awesome it is to receive sports cars as a gift, or maybe she was just trying to outdo "Lamborghini Mercy." The car plastered tabloids recently when it was scraped up by Kim's electric driveway gates.
Ferrari SP12 EC

The Ferrari SP12 EC was a one of a kind car specifically built for Eric Clapton. The SP in the name refers to their 'special programme' that makes these custom cars. The car is mostly a combination of the 458 Italia chassis and the 512 BB body kit.
Porsche 959

Seinfeld boasts an impressive, partially secret, collection of Porsches of all kinds and ages. One of the coolest cars in his collection is the Porsche 959 which was the fastest street legal car when it debuted in 1986. It was technologically advanced for it's time and set a precedent for many sports cars of today.
EcoJet

The EcoJet was a concept car designed specifically for Jay Leno to be driven on the road and not just kept inside a garage. Instead of a piston engine, it has a turbine engine like a helicopter, and uses half jet fuel and half biodiesel fuel. The heat output is over 1000 degrees and since it runs on refined cooking oil, it smells like cooking french fries.
Smart Clown Car

I won't go as far as to say this car is that cool on it's own, but watching Shaq cram into a Smart Car makes him look like he belongs in the circus.