best undead dragon template

[Baby Gary]

which is better, skeletal dragon, vampiric dragon or zombie dragon? (all from draconomicon)
I think vampiric, It can still fly perfectly well (also walk) has ability buffs, does not loss INT, keeps all Special abilities/qualities and gains quite a few new ones, keep skills and feats and gets quite a few new ones, and gets a Natural Armor buff.

[Waker]

I don't have the book in front of me, but why aren't you including dracolich?

[Zanos]

Vampire Dragon's are unquestionably the best, that isn't even a debate. They vampire dragons get a whole bunch of amazing stuff and keep all their normal abilities like spellcasting.

They aren't competing in the same niche though. You can't usually create vampire dragon minions, whereas dead dragons make great mindless servants/blenders for an enterprising wizard or cleric with moral flexibility.

In that vein, the zombie dragon retains a half-strength breath weapon, which is amazing if you can get a dragon corpse way above your CR and animate it. You can also awaken it to take metabreath feats, which is amusing. The zombie dragon keeps it's fly speed as well, so you can make a big ol' taxi for their party to places you can't teleport to.

The skeletal dragon keeps it's full attack and is a melee blender, but loses pretty much all the special stuff.

Both have an interesting little tidbit in them, though "Size and Type:The creature’s type changes to undead. Do not recalculate the creature’s base attack bonus, saves, or skill points. Size is unchanged."

This is massively advantageous, meaning that a dragon zombie or skeleton has BAB equal to it's HD instead of half, and base saves equal to 2+1/2 HD instead of 1/3rd HD. And awakened dragon zombie/skeletons get 6+Int modifier skill points per HD instead of 2+ int.

[Almagesto]

Vampire Dragon's are unquestionably the best, that isn't even a debate. They vampire dragons get a whole bunch of amazing stuff and keep all their normal abilities like spellcasting.

Second that. Vampiric dragons, however are so OP that I don't know if this is what you're looking for. If you want to reanimate something to serve you, go with the combo from K's Necromancer Handbook (http://brilliantgameologists.com/boards/index.php?topic=5584) and use zombie with awaken.