Refluffing existing creatures

[Yora]

I am doing a bestiary for my campaign setting and realized that a huge amount of ideas can be quite easily done by taking existing creatures and changing just two or three stats and the description of how they look.

Which such quick and dirty conversions have you done?

Scandinavian troll - Ogre. Done. Duh!
Sidhe - Janni genie, with slight tweaks to the SLAs.
Deep One - Skum
Spriggan - The Elder Scrolls plant person/4th Ed. dryad kind. An advanced 8 HD medium sized Kodama. And that's it, nothing else really left to do.
Draugr - Wight (and not really a refluff, they are virtually identical)
Skever - Dire Rat (maybe advance to 2 HD)
Barghest - Like the ones from the Witcher. Take a Yeth Hound without flight.
Charr from Guild Wars. Take a Minotaur without Natural Cunning and add +2 Int.
Low-level Specter - Apply both the zombie and ghost template to the same creature.

[Zombimode]

The quickest and dirtiest conversion was:

Vampire Bat: Stirge. Yeah, and then the Ranger was rightfully pissed that his Favored Enemy (animals) didn't work...

[Telok]

Lava Snakes: I took a Salamander, changed the spear to a bite and it's type to magical beast. Drop the Int to 3 and take away language and speech.

For bigger ones I took the salamander noble and stripped out the spell-like abilities except the fireball which changed to a 60' cone breath weapon.

[Asrrin]

I heard someone mention on these boards that they wanted a BBEG human Wizard stats and had to improvise, and ended up refluffing a beholder to do the job in a pinch.

[yougi]

I do it all the time. In my campaign setting, the main "enemy" is the leader of this cult which brainwashes people and transforms them, mutates them. To stat these guys, I just refluff other creatures. I've done it with pretty much every monster with at least one nifty ability up to level 10-12. I often add templates that don't make sense, or classes. I used every single dragon color at least once, and grimlocks everywhere (whenever I have creatures with gaze attacks, I put Grimlocks with them, but I don't want my players to know how lazy I am).

Just last week, I've used a Razor Boar with lots of Willing Deformity feats, and refluffed him as a Cyclops with elephant-like tusks; I've taken a Wyvern, given it Barbarian levels and refluffed it as a flying rhino; an advanced Manticore with the Feral template (yes it's illegal, so what?) and refluffed it as a Barbarian from a feline-like race.

And they all worked great. They keep players on their toes. They don't know what it can do, just like true adventurers who have never encountered a Troll.