Sinister Schnoz

Almost anytime a character has a large nose, he's a bad guy. Villains have big noses. They might be long and pointy, or a giant hook down their face. But for whatever reason, bad guys rock the big noses. Maybe it's symbolic of how ugly they are on the inside? Maybe it's just to distinguish between the honest good guys and the less honest bad guys for the audience. No one knows.

It's one of the great mysteries of life.

This is also part of Antisemitism. In anti-Semitic propaganda, Jews are depicted with big noses, way beyond normal. This can lead to Unfortunate Implications if it is used in other contexts.

It's also sometimes done in Japanese Anime, but this is reference to Tengu, who are said to have large noses.

Examples of Sinister Schnoz include:

Anime and Manga

Dog Master Galf in Fist of the North Star.

Comic Books

Iznogoud. Just look at him.
Rastapopoulos in Tintin.
Crimson from the Belgian comic series Suske en Wiske.
Why else Penguin would be called such, aside from his short stature?

Film

In The Wizard of Oz, The Wicked Witch of the West.
The Child-Catcher of Chitty Chitty Bang Bang.
The title character from Ink. Often, it's all you can see under his hood. His angst over his ugliness helps drive the plot. Subverted by the end, when he pulls a Heel Face Turn and decimates the "pretty" Incubi.
The many villains played by Basil Rathbone.
- Alan Rickman's nose is emphasized in his villainous or morally-ambiguous roles.
- And Geoffrey Rush.
Gru of Despicable Me. A subversion, that while he is a villain, he's actually a good person.
Watto in Star Wars Episode I: The Phantom Menace has a huge nose, which contributed to the case of critics who called him an antisemitic stereotype.
In Monty Python and the Holy Grail, one of the signs of a "witch" is having an extra-long nose. However, the nose is fake because the people put it on the woman in question. This IS a general characteristic of wicked witch characters in fiction, though.
The main villain in Apocalypto was given a larger, prosthetic nose, which Mel Gibson points out in the commentary.

Literature

Harry Potter
- Toyed with in Severus Snape.
- Averted with Voldemort, who has two slits in the middle of his face, like snake nostrils.
Hotzenplotz and Zwackelmann from Robber Hotzenplotz.
Sherlock Holmes is a hero, but his nose is frequently described by Watson as hawk-like: large, aquiline, and pointy. Combined with his gangly physique, Holmes strikes a severe but not dashing figure. Doyle was always annoyed that illustrations made Holmes too traditionally handsome and heroic looking.

Live Action Television

Fenella the kettle witch from Chorlton and The Wheelies.
This is taken Up To Eleven with Nayzor, one of Master Org's commanders in Power Rangers Wild Force. His entire face is a nose, with his eyes in the nostrils. Yuck.

Music

The Boogie Man from Gorillaz has an extremely long nose. It's the only facial feature visible. Murdoc also has a rather bulbous nose. He's not technically a "bad guy", though. YMMV.

Tabletop Games

The Gretchin of Warhammer 40,000 have ridiculously long noses that take up half their head. The same is also true for their Warhammer Fantasy Battle equivalents, the Goblins.
The picture shown for the Imp (a minor devil-like creature) in the Monster Manual for 1st Edition AD&D has a schnoz that would make Jimmy Durante jealous.

Video Games

Phoenix Wright: Ace Attorney: Luke Atmey.
Ganondorf of Zelda could open a can of Coke with his sniffer. Interestingly, it goes from straight and needle-like to hooked and bent. Averted when he turns into his pig-form, where he gets a snout.
- Ganondorf gets his long nose from his race: the Gerudo, a race almost entirely made of women who work as thieves. It's subverted in their case because the Gerudo are actually quite nice to Link once he proves himself.
Warcraft goblins are more neutral than evil, but still have long noses.
- While the Steamwheedle goblins are just shrewd businessmen, the Bilgewater goblins added in Cataclysm are more like gangsters. Their mob boss, Gallywix, even built himself a pleasure palace in the middle of Azshara with its own mountaintop golf course.
- In Uldaman, the main villain for most of the quests is a Goblin tresure hunter and his mercenary army that are working for Deathwing. He's named Schnoz.
Tengu in Dead or Alive 2. But he is a Tengu, so that is given.
Toujin the assassin from Battle Arena Toshinden 3.
Heiss in Radiant Historia.
Loghain of Dragon Age, who looks rather like Alan Rickman in general.
Patches of Demon's Souls and Dark Souls.
Mordroc, the Big Bad of Dragon's Lair II. Not only does he have a huge nose, there's a branch growing out of it!

Web Comics

Diego from Gunnerkrigg Court.
Schtein, the Villain Protagonist of String Theory, provides this page's image.

Western Animation

The Simpsons: Mr. Burns
The Looney Tunes cartoon "The Dover Boys of Roquefort Hall" had such a villain in Dan Backslide.
Dick Dastardly in both Wacky Races and Dastardly and Muttley in Their Flying Machines
Snidley Whiplash from Dudley Do-Right.
Dr. Doofenshmirtz, the Affably Evil villain from Phineas and Ferb, has an impressive one. It was even lampshaded once:

Doof: Is my nose really that pointy?

Quite a few villains in the Disney Animated Canon, e.g. Frollo, Jafar, and Captain Hook.
The Ice King and Lemongrab from Adventure Time.
Corvax from Muzzy in Gondoland.
Starting with Batman The Animated Series, every single villain in the DCAU has a nose you could pop a balloon with. Every. Single. One.