I probably missed out on a lot of stuff like that because, in BGI especially (where my saves were crap,) I lived in fear of ever letting wizards get off a spell. I stocked up on poison arrows at the first opportunity and hoped my specced fighter could get a few into him and he failed his saves before he could cast, so the per round damage ensured he never DID cast.

Yeah, lightning bolts are sweet though. Except for that chess match in Durlags Tower, but you can use that to your advantage if you have enough HP and/or some anti-magic potions handy.