I have to say that Races of Destiny gets a big meh from me from what i've read of it. A big racial book on playing humans. Wow, like I really need tips to play a human character, or I need more insight on human society. Ok, so there's stuff on half-elves and half-orcs as well, but I don't know or care if either are done well. The half-races essential fit a sort of cliched half-breed niche already. I really don't know if this book adds to that. I usually don't play either race as a player, and as a DM I don't really do anything with them as a whole, using such NPCs as individuals, rather than actual societies.
Then there's these illumian guys which don't interest me at all. The last thing I need is yet another fantasy race in my campain. I can get plenty of milage out of human, dwarves, elves, halflings, gnomes, goblinoids, kobolds, orcs, and gnolls, and even those seem like too much sometimes. The chapter on stuff like planetouched and mongrelfolk seems off the cuff to be really to short to cover them in any detail. Feats, PrCs, domains and other such crunchy bits aren't bad, but there's enough of them now all over the place that this book really isn't screaming "Buy me!" to me.