Unless I'm mixing things up with IWD2, aligment has (very slight) effect on Cleric's spell selection. I remember that evil clerics get Gate for example, and good ones don't.

Is there any rundown of what spells which alignment gets? I'm especially interested in x Neutral.

Neutrals get pretty much everything. IIRC there was a time that evil clerics got Unholy Blight and good clerics Holy Smite, but that's the only difference. Neutrals get both.

There is also (Un)Holy Word and the Deva HLAs. On the whole, however, the differences are very slight.

Yeah, but IIRC they could only choose one out of the two spells. eg, if they chose Summon Deva they can't also get Summon Fallen Deva.