For my first character, I decided to choose the one and only Wario.
“So admit it..... Don't I look cool in the game screens? Those long, muscular legs on my sturdy toned frame.... I'm the perfect specimen of a man..... What!?!? You say I look fat and my quadruple chin looks like a waterfall of flab? Shut up! That's just because you have your television set up on widescreen display!” —Wario
Wario is very unique among the Nintendo staple of characters. He's not a villain, yet he isn't a squeaky clean guy. If he saves the princess it's likely because the king offered a huge reward. He will cheat anyone out of their money, no matter if it's an old disco dancer or a pair of adorable ninjas. Yet you will likely never see him hit or bully anyone weaker than him…unless it's the enemy and it's preventing him from getting the treasure.
My first exposure to the character was through Super Mario Land 2. It was one of the first Game Boy games I ever played and I loved every minute of it (as a tangent…Nintendo…Virtual Console Game Boy…DSi…make it happen). Once I worked hard and completed the game's worlds I finally gained entrance to Mario's castle so I could battle the bad guy. That's when I first met the anti hero we know and love.

It was very weird. He wasn't Bowser, but he still managed to grab my attention. He looked like Mario and used Mario's powers, but he was large and disturbing. Once I beat the game Wario's image was burned in my mind as one of the weirdest Nintendo villains yet. So imagine my surprise when I learned that he got his own game in the form of Wario Land: Super Mario Land 3 for the Game Boy.
Of course I HAD to have it, and once I did, I started playing and never looked back. I wanted to play it because it looked like a Mario game and for the most part, it played like a Mario game, but with enough unique elements that made it a Wario game.
So from that moment on, Wario became one of my favorite Nintendo characters. And just in time, too. Just as Mario was expanding his gameplay horizons with parties, kart races and other sports he needed more friends to join him. Wario was always the first to attend, creating even more awareness of the character.
My interest for the character, however, was intensified in the Gamecube and Gameboy eras. With technology being able to make more colorful worlds and make characters even more alive, Wario truly became an unforgettable character. He was more in your face, greedier, and cartoonier than ever before. The differences between him and Mario were even more apparent. The advanced sprite capabilities of the Gameboy Advance made Wario very noticeable in Wario Land 4. It was truly the pinnacle of what could be done with the character… until Wario Ware: Mega Micro Games was announced.

With WarioWare, Wario became an even greater character for me. He became one of the few Nintendo characters outside of Mario to have dual roles as both a treasure hunter in a fantasy world and a greedy businessman and game developer with some very original characters in each setting.
As I already explained one of the reasons I love Wario is because he is unique in both the Mario universe and the whole Nintendo canon of characters. Nintendo characters are either nice, squeaky clean, and well intentioned heroes, or are very evil, nasty, and very dark bad guys. Wario is stuck in between. He is not quite evil, yet he is not a good guy. He is ugly, fat, and obsessed with money and anything of value, but seems to have a bit of an honest side to him since he is rarely seen done anything truly evil. He might cheat, steal, and gross everyone out with his nuclear farts, but not to the extend of say Bowser or Ganondorf (as an FYI I realize that he was one of the primary bad guys in the story mode in Brawl, but since that isn't considered canon I conveniently toss it).
Wario is currently voiced by Charles Martinet, who also does Mario, Luigi and Waluigi. That's another reason why the character is so likable. Mario is the nice guy; Wario is the greedy guy meaning that Charles has more material to work with when he's Wario, especially when he is playing the character at special events in the Nintendo World Store in New York.
For me it's hard to pick a favorite Wario game since nearly all of them are very solid and even fantastic in their design. The only stinkers would be Wario World on the GameCube, which was still a fun and solid title, and Wario: Master of Disguise on the DS. Every Wario game has something about it that make it great among the titles in the series. For example, Wario Land 2 introduced the "no death" mechanic, which made Wario turn into a different form (such as a snowball and a zombie), and the different paths that lead to a different ending each time (my favorite to this day is the path you take if you decide to not get out of the bed in the first stage). Wario Land: Shake It! on Wii had a stunning 2D look with some solid motion controls and a balanced level of difficulty. Finally, the WarioWare games shine because even if they are the same the concepts change. So one minute you are pushing buttons (Wario Ware), twisting the GBA around (Twisted) or dancing like an idiot (Smooth Moves).

There are many other reasons why Wario is a great character (to me at least), but it would be a very, very long article due to the fact that his story is very complex and filled with some incredible and fun games.
So what do YOU think? Do you have a soft spot for Bizarro Mario or think he should be burned alongside the other supporting characters? What is your favorite Wario game?