Could the odds have gotten much better than this?* Tiffany and Keir each had a 50/50 chance of winning. See? This is why it's always worthwhile entering these kinds of contests. Your odds of winning increase 100% by entering.
Since Tiffany was the first to enter, Tiffany D is the winner!
Tiffany: Please email me with a shipping address and I'll get the book off to you this week. (I can be found as fivecat over at gmail)
* Theoretically, yes, the odds could have been better. If Kier hadn't entered Tiffany's odds of winning would have been 100% but then it really wouldn't have been a contest, then, would it?