And just to add, HC/ATT aren't the only settings that should influence your race... for example:
-Spawn bonuses are more effective on large maps, and meaningless on really small ones.
-Lots of people use the Undead to conserve boosts and protect against the occasional surprise bad luck.
-Frankensteins and (to a lesser extent) werewolves are particularly good on full map games for obvious reasons.
-Teddies are great if you want to prove yourself
-Santas are great if you want to get shards faster
Personally, I use werewolves a lot. They're pretty good for most game settings, but more to the point it was the race I had wanted from the beginning. They just look good (even more so in between their first release and the shards release because almost no one had them), and everyone knows the most important part of VW is looking good.
But seriously, don't forget to play with the Dark Knights and Reindeer (and Blade Masters, Snowmen, Pirates, Cyrborgs, etc.) from time to time. If we neglect them for too long, they'll become vengeful and haunt your computer.