I'll start.
My favorite performance is Jaheira, voiced by Heidi Shannon. That unique, eastern-european accent saying "Yes, oh omnipresent authority figure" is unbelievably iconic and also perfectly captures BG's slightly irreverent tone. It's emblematic of the series as a whole, and probably influenced a lot of fantasy RPG voice acting that came after it. For example, I am convinced that Laura Bailey's character Jester in the second season of critical roll was based on Shannon's performance, though admittedly the personalities of Jester and Jaheira are quite different.
And you know what's surprising? Heidi Shannon didn't go on to do anything else. Nothing that I'm aware of anyway. And I have no idea why. Makes me wonder if the voice actors back then knew that they were working on a very influential title, or if they just recorded those 2 minutes or so of voicework for that weird little game company just to pay some bills.
I will always love Jon Irenicus by David Warner. When I was young playing BG2 as non English speaker for the first time that crisp and sharp English pronunciation stuck in my head as I was able to understand it clearly. That voice is perfect fit for the character of Jon too.
Later I was surprised I saw David in one of Terry Pratchett 's movie Hogfather as Lord Downey - there was something behind his voice familiar to me but I could not put my finger on it - later when he died I read one article where both voice acting for Irenicus and his role in Hogfather was mentioned.... aaaand it finally clicked in my head ..that strange feeling of realization :) I love BG and Pratchett's books and movies very much.
That's awesome. I originally played BG2 in german, which also had great voice acting, but I just relistened to irenicus voice lines on youtube, and it is actually quite different. The english performance feels almost shakespearean. It's really great. I also wasn't familiar with hogfather, guess that will go on my to-watch list.
I cannot recommend it enough, it's a great movie. I watch it every Christmas.