If you play a good party in Baldur's Gate 2, it is very likely that the vampiers of Amn become your enemies. That means that you can't go out and buy a bottle of milk in Amn without being attacked by a bunch of vampires, and they make very short work of your heroes unless they have "Protection from Undead". Also, the vampires are immune to normal weapons. That means that your archers and slingers have to switch to +2 shots/arrows everytime they take a walk in Amn, and that you group your heroes together to cast the Protection spell on them all at once. The spell lasts for an inconveniently short time too, so you'll have to do this pretty often. If you don't have mapped a lot of Protection from Undead castings on your casters, you also have to go to sleep a lot to regain the spells you've used up. That's just how Baldur's Gate 2 is.
Thanks for warning me.
He is exaggerating though. Just putting a few copies of that spell in your spellbook along with restoration deals with vampires (and other undead, Ghouls do this too iirc) just fine and if you play your cards right you shouldn't even be needing the latter all that often (or if it bothers you: get a wand with the appropriate spell assuming they exist, I dunno): your fighters should be taking most (preferably all) of those hits. It's generally fairly obvious when you'll run into undead too, just prepare accordingly.
Note also that vampires only become "common" after a certain part in the story and if you still have trouble dealing with them by then you're in for a real treat later...(hint: buy the Shield of Balduran from the bonus merchant in the shop on Waukeen's Promenade. You can thank me later.)
Not that there aren't many plain annoying enemies or mechanics in the game, but I wouldn't consider Vampires among the worst, sure their ability is a pain if you're badly prepared, but it's easy enough to deal with as they just drain strength. Now Mind Flayers (HAI! I drained ur int, now u can fill in ur spellbook again! Heehee!) and Elder Orbs (well basically everything that casts Imprisonment or any other spell that *removes* someone from your party)
Ofc if you are low on "healers" it might be more annoying to deal with Vampires, my favourite party for the first part of the game was: me (wizard), Minsc (and Boo), Jaheira, Viconia, Korgan and Yoshimo.
