I mostly play humans in any RPG setting, but as this is about D&D:

- Most cultures of the Faerûn I'm interested in are human (Reghedmen, Uthgardt and Northmen of Ruathym/Moonshaes, Ffolk of the Moonshaes)
- Humans are pretty diverse culturally and allow for interesting roleplay

Apart from humans I (very) rarely play half-elves and dwarves (Shield dwarves usually).

And quite frankly, I've rarely seen well-played dwarves, elves or any other non-human races. Most people play them as humans with weird ears or as stocky, grumpy, constantly drunk humans with beards and that doesn't do their cultures remotely justice.