I nearly had fits when Eladrin, Tiefling, and Dragonborn were included in the 4e PHB simply because I didn't know how to fit them into my homebrew game, because I didn't want to be the guy who says "the PHB is legal, except for X, Y, and Z." After giving it some thought, I was able to squeeze Eladrin in pretty easily - I had already created 2 distinctly different elven communities in my world - the one we're familiar with (fey humanoids prancing about in the leafy forest), and one that lived a hardscrabble existence in a ruined, demon-warped, blasted desert landscape. I decided that the elves were the progenitor race, and when the destruction of their homeland began, they fled to the untainted, forested lands to the north. Those who were left behind were changed out of necessity - to survive, they became the Eladrin. Very, very little ret-conning was necessary.
Dragonborn required more thought - I ended up making them natives of a small part of a recently "discovered" continent and thus were very rare in the wide world, but still easily explainable.
Tieflings...I hate them. I readily admit that. I. just. don't. like. them. Can't say why. But they leave a bad taste in my mouth. Even so, I just decided they weren't a race. Like someone posted above, I shoehorned them in as specific individuals - the offspring of the twisting mating of a human and a demon. If you want to be a Tielfing, you can be a Tiefling. But know that you've got some nasty baggage that you're carrying with you.
PHB II races really weren't so bad after I figured out how to handle the PHB I oddballs. Goliaths live in the frozen far-northern mountains and they comprise a tiny, tiny, tiny population. Gnomes were always there, but they resemble their 2e incarnation. Devas are angels who have chosen to dwell with mortals. If you're a Deva, you're a one-a-million. Don't expect to see another one in my world unless it's for story reasons. Half-orcs were always there, they weren't an issue.
I don't like monster races, and the PHB III really seems like it's tailored to the player who wants to be a real off-the-wall character. But, if a player came up with a REALLY, REALLY good justification for why your minotaur isn't raiding a mountain village with his brethren, then we can probably make it work. If you can justify why your Gith isn't struggling to just NOT DIE in the Abyss, then we can probably make it work. I won't like it, but we can probably make something jive. That being said...if it's a deal-breaker and I think it will destroy the flavor and tenor of my world, I'll say no. I hope I never have to do that, but I'm prepared to.
TLDR: I have had to give it some thought, but I've had good luck fitting most things in. I don't want to out-right ban something, but I'm prepared to do so if need be.