Neprostoman pretty much covered all the spells.
- Speak With Animals
- Speak With The Dead
- Detect Thoughts
As far as races go though, the most meaningful are:
- DROW - They get the most unique treatment, dialogue choices and even Drow specific scenes. On top of that both Lolth-Sworn and Seldarine Drow each have their own unique dialogue choices which are very interesting and opposite of each other.
- GITHYANKI - Second best to experience different treatment and unique dialogue choices, especially when it comes to a certain companion.
The rest of the races however pretty much receive the same treatment and similar dialogue choices. Naturally they all have some unique acknowledgements from NPCs around the world and dialogue choices, but Drow and Githyanki are on a completely different level when it comes to the amount of world immersion, scenes, acknowledgement and unique dialogue choices.
My favorite are definitely; Drow, Githyanki and Tiefling.
As for classes... that would be impossible to even begin comparing as every single class has unique dialogue choices and flavor, depending on the situation. Barbarians for example have unique choices where they lose control, can smash things open and intimidate people. Rogues get unique choices when it comes to shady deals and scams. Rangers get unique choices when it comes to wilderness and survival. Clerics get unique choices when it comes to religion and Gods. Sorcerers can recognize magic in the air. So each class has unique dialogue depending on the situation.
