Love it, really. I don't think the gith is off at all - they're humanoid after all and the "they're evil and nasty so they have to suck and look like your worst nightmare" always sucked.
Love the handsome half-giant - he's definitely the one I like best on that picture. And the scars that everyone has - and that gith tattoo.... *drools*
I have to agree with creeper about height and proportions though - the halfling seems way too small (even if I think he looks just right for anythign except size) - maybe you choose heights in the upper limit for most races and made the halfling at the lower limit? Even if the human is six feet tall, the halfling isn't even half her size and would still be under three feet - I'd go for average heights for all races.
About leg length - it didn't stick out to me at all, not now that someone said it, I noticed something, too - compare the half-elf and the elf. The elf is way taller than the half-elf, is standing on his toes and still her waist and backside are at the same height as the half-elves, if not a bit lower.
The dwarf doesn't seem that skinny to me, but the right arm seems off compared to the left one.
Still, this seems absolutely awesome - can we have this on the website? Preferrably very close to the homepage?