dtgreene: Actually, the game isn't turn based. Everything happens in real-time; it's just that there are a lot of cooldowns involved. (For example, after starting to use a spell or item, you can't use one for about 6 seconds, but (if you aren't still in the casting animation), you can still move or even attack. This becomes noticeable, for example, if you have a character use a potion in melee and then immediately go back to attacking.)
thejimz: The developers themselves considered it a turn-based game. It just has a lot of added animation to makes it seem real-time. Obviously, it's not a perfect reconstruction of the D&D ruleset, but it's still not a proper real-time RPG like Diablo.
What I'm saying is that it is not just the animations that make it real-time; it's the game mechanics.
Here are some other examples:
If a fireball has been cast, it is possible for the target to move out of the way before it hits. Alternatively, you could open the character's inventory (which in BG2 pauses the game) and equip a ring of fire resistance before the effect lands. (You can't change armor when the game thinks you're in combat, but other equipment can be changed.)
Sunfire makes the caster briefly immune to fire. A well timed sunfire can allow a mage to avoid damage from a dragon's fire breath, for example.
If a creature is hit by multiple spells on the same frame (unlikely unless a sequencer with multiple spells with the same projectile type is used), the same roll is used by all saving throws.
With ranged attacks and spells, double kills are possible. A can attack B and B can attack A before the attack lands, and if both attacks are fatal, a double kill will occur. (No need for area of effect attacks here.)
The behavior of some sequencers and chain contingincies depends on the animation length. (In a turn based game, the first effect would complete before the second effect starts; that's not the case in Baldur's Gate.)