Of the two brothers, Dean certainly has his younger brother Sam beat in the looks department. With his gravelly voice, can-do attitude, and take charge personality, Dean Winchester has quite the reputation. On both sides of the supernatural fence.
Typically clad in a flannel shirt accompanied by his father's old leather jacket, Dean has been portrayed as mischievous, funny, and in some instances a tad immature. Yet he is also fierce, a born leader and tactical genius.
Despite all his silliness, Dean does take one thing seriously: his little brother Sam. Dean has moved hell and earth, even sold his soul (literally, he did that at the end of the second season) for Sam. However, for all his virtues he does have many faults. Known as ruthless during his hunts, Dean adopts his father's style to hunting: shoot first and keep shooting.
He is more likely to exhibit irrational and impulsive behavior when his family is threatened, which makes him a feared individual.
Roy: Killing Sam was right but Dean...
Walt: He made us and we just snuffed his brother, you idiot. Do you want to spend the rest of your life knowing Dean Winchester's on your a**, cause I don't.
An avid lover of movies, Dean will geek out over various things like medieval roleplay, Scooby-Doo, he can quote Star Wars, and has a working knowledge of Harry Potter. He will use aliases that are shout-outs to classic rock bands like AC/DC, Metallica, Led Zeppelin, and Kiss.
Take away his bravado, weapons training, and chiseled jaw, and Dean Winchester is merely a mal-adjusted fanboy with a pie addiction.
The Impala aka Baby is a character of the show unto itself.
This is Dean's most prized possession, a car passed down from his father and one of the few heirlooms they have left. Although the car has been totaled on more than one occasion, specifically at the end of season 1, Dean has rebuilt and restored this beauty from the ground up.
No one drives Baby except for Dean. If anyone approaches that even looks at the car the wrong way, Dean has been known to lash out in anger and aggression.
Sam: If somebody stole the impala, what would you do?
Dean: Murder. I'd murder them all...There would be torture first. There'd be a lot of torture. And it would end up with death. If I can't have it, nobody can.
An actual conversation from episode 13x15 about the impala.
Often used as a cache for weapons, this symbol on the inside of the hood is known as a Devil's Trap. It is a magical symbol that renders any demon powerless. They wouldn't be able to open the hood and rifle through their sensitive and dangerous weapons. Also, should a demon be locked in the trunk (as it once happened to the demon Crowley), it would not be able escape or use any of their powers. They would essentially be a normal human locked in the trunk of a car.
The Winchester weapons cache while they're on the go. They have pistols, shotguns filled with rock salt (it repels ghosts and demons), grenades, various items to use for spell work, ammunition, their father's journal, brass knuckles, a stash of holy water, harpoons, axes, and several other items. It's an arsenal.
My Dad Had That Car by 
Art of American Automobile by 
The American Automobile by "Fight the fairies! You fight those fairies!" - talking about actual fairies in episode 6x09
"Driver picks the music, shotgun shuts his cake-hole." - to Sam in episode 1x01
"Eat it, Twilight!" - to a vampire he decapitates in episode 5x03
"Alright, let's do this. No flirting you two." - to Sam and Cas just before they enter a retirement home in episode 8x08
"She's kinda like the little sister I never wanted." - to Sam about their new friend Charlie as she leaves town in episode 7x20
"Well, now what we have here is a failure to communicate. 'Cause we're not trapped out here with you, you're trapped out here with us." - to government agent chasing the Winchesters through a forest in episode 12x09
"Keep fightin'. Take care of my wheels. Sam, remember what Dad taught ya, 'kay. And remember what I taught ya." - to Sam in the final days of his contract after he sold his soul to bring Sam back to life in the previous season in episode 3x16
"Yeah, well I kill Gods." - to a sheriff of a small town as he tells Dean that the Styne family are practically gods in their community in episode 10x22