I’m a bit torn between human and dwarf. I tend to prefer humans for my arcane and roguish characters and dwarves for my divine and warrior type characters, but I don’t tend to favor one over the other. For instance, in the Shackled City campaign I played human bard. I was only moderately interested in him as a character, but was not disinterested enough to have him written out or killed off. It’s the only time I’d played a bard and wanted to see it through at least a ways. Through some events, he eventually had all his bard levels changed for a modified/custom cleric class. He ended up being one of my all time favorite characters, even though most of my clerics are dwarves.
Another of my favorite characters was a dwarven cleric who found himself travelling through White Plume Mountain in Greyhawk and ended up with an extra eye in the back of his neck, the ability to cast fireballs and believing himself to be Keraptis. That was a lot of fun.
On a couple of occasions I have played an elf, but I always play them as an outcast who cares little for the rest of elven civilization. That’s primarily because I find elves annoying in general. Well, at least pre-Lord of the Rings movies they were annoying.