In no particular order:
Changelings - I keep playing them, despite everytime I end up wearing the same face most of the time. But I still love them.
Warforged - As you can probably guess, Eberron is my favourite DnD campaign setting. And I quite like the warforged.
Eladrin - I prefer a more fey elf, and I like the otherworldly nature of the Eladrin
Thri-Kreen - I'm not sure how much I like gritty, dark games, but I do like Dark Sun and 4-armed Mantis hunter people.
Pixie - I get that flying can be problematic for DMs, which is why my preferred flying lineage is a tiny fey spirit.