Well, Echidna is the mother of all monsters, mythologically speaking. So maybe you have a point >:}
Au Ra - Xaela. Mostly prefer the dark horns, and I like the lore better. Also the light horns/scales just makes me want to make blonde jokes. ^^;
Roegadyn - No real preference, but generally Hellsguard because they have names you can actually pronounce (looking at you, Admiral Blowfish! D: )
Hyur - For female, definitely Highlander, due to how expressive their emotes are. And also because they don't look like teenagers but actually adult women. For males... It depends. It's very easy to make ugly highlander men, so that's a negative point in my eyes. Same with the eyebrows. Have managed to make a decent Highlander retainer, though.
Lalafell - I do like the creepy effects you can get with Dunesfolk eyes. But I like the patterns for Plainsfolk names better.
Miqo'te - Both. Both is good. As my name shows, I started out as a Seeker (and accidentally ended up with nearly exactly Kobold Brown skin. All hail nekkid suits!), but that's because I wanted the slit-pupil look. On the other side, Keepers have them fangs ♥ So yeah, both is good.
Elezen - No particular preference, really. Potentially Duskwight comes out slightly ahead for the skintones. And because it always annoyed me how the Wildwood elezen dude in the Archer training hall was all "pfft, you're not a Wildwood, you can't understand archery", even if you are a Wildwood elezen! *grumbles* Sure, NPC dialogue programming and all, but it would have been such an awesome thing to do if they'd decided to put in a small racial check in that dialogue and change it slightly if it was a Wildwood PC.
