Good idea, I'll throw a few in.
Title: Castlevania: Legacy of Darkness
System: Nintendo 64 (May have ported to something else, I don't know. I only know it was there first)
Genre: Platformer/Action game
Werewolf: Cornell and one Boss
Cornell is one of the major playable characters in the game. His storyline is more or less the "main" one since well, Reinhardt and Carrie, the other two MAJOR characters were already featured in a previous Castlevania (Castlevania 64) and well, their storylines are pretty much the same.
Cornell's from a village of Manbeasts who sealed their beastforms so they could peacefully live alongside humans. He's the only one to break the seal ( Spoiler: [spoiler]Aside from Ortega, later on.[/spoiler]) and release his form.
He did this in a remote location however, and when he gets back the village is in ruins and his sister's been kidnapped, thus drawing him into the story.
As far as playing goes, Cornell can easily switch between his lycanthropic form and human form, using thrown energy bolts (like Carrie) at range and claws at close range. Is transformations are powered by the red jewels the game uses to give you ammo for thrown items like axes, holy water, etc. so you are forced to use it wisely.
The other werewolf is one Ortega traps him with on a platform during one of the levels. Aside from being a big a** lycanthrope, there's nothing really spectacular about the guy.
Image(s):
In-game, human
Art, Human
Concept Art, mostly human - one sketch of werewolf form
Werewolf form, taken from guide. Looks a little less cool in game due to the old graphics.
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Title: Vampire: The Masquerade: Bloodlines
System: PC
Genre: RPG
Werewolf: There are two, but aside from watching one tackle your buddy off a cliff, then later see aformentioned were's head on your buddy's bed in his motel room, the player only encounters one. Also. A werewolf cardboard cutout target.
The Lycanthrope is impossible for the player to slay by conventional means (I guess it has to do with being a recently-made vampire, since while your buddy is 100 something years old he seemed to do fine aside from some light mauling) and the player has to go through a complex process that ends up with closing the doors of the observatory you're near on the poor bastard to kill him.
Or you can run around for five minutes until the lift arrives and takes you away from him. Which I prefer as all he did was find his forest on fire and assumed the only two guys around were the ones that started it. But..kiling him give good XP.
Image(s):
Doing a dance number with my vampire. Okay. Not really. I made the mistake of attacking him and managed to get this screeny by luck. I died shortly after. 
His dramatic entrance (The forest is on fire because someone set it on fire to rile the werewolves up. )
The head of the guy who attacks your friend.
The only target more hilarious then this one is the vampire one, which shows dracula.
Title: The Elder Scrolls III: Morrowind GOTY Edition (Or Morrowind with Bloodmoon expansion pack)
System: PC and X-Box
Genre: RPG
Werewolf: The player can become one, and the island of Solstheim holds 9 ones you can run into randomly (though the chances are low) and if you do the Main Quest that's availible in Solstheim you'll run into dozens of them.
Gameplay wise, a werewolf in MW is incredibly fast, and insanely strong, but frail due to the fact that the "unarmored" skill bugs out and leaves the WW with no protection beyond his ability to dodge, run, and jump like crazy. They're also sneaky. So for the player the strategy is to sneak and slay foes, or use hit and run tactics. To kill them, a silver weapon and a good amount of skill is all that's needed. AI is simple and will simply rush you and attack, allowing you to hit them easily. But the NPC weres can do some serious damage, players playing on the hardest difficulty have had their shields shredded in only a few blows.
They - like the player - only possess three attack animations (left, right, and downward claw, all two-handed claw swipes) but if you ready your claws (by "unsheathing" them like you would a sword) you move around two legs, when you "sheath" them however, you move around on four legs.
Additionally, the player has to slay one NPC (not a creature - an NPC. Meaning a character of one of the playable races) to statiate their bloodlust or their health with slowly drain. You will not DIE from this, but you'll be half dead by the time you're awake. Conversely, slay an NPC and you'll gain a slow 1 HP per second health regen. You also shift to WW form at exactly 9 PM (with a cool movie, too!) and back to human at 6 AM.
When you return to human you're naked and must re-quip your stuff (this is the extent of realism with the shift. None of the stuff you were wearing is ruined and you somehow managed to carry all your stuff around). Silver will deal double damage to you, etc.
And you get a nifty soundfile played if you try to do something you can't (a whimper, howl, etc.) and in first-person view there is fish-eye bending and a red tint.
Image(s):
The werewolf Ingame
Concept Art
I'll throw in more as I think of 'em and more people post.
