I remember Baldur's Gate coming on 5 CDs, heh.
Story time!
I was managing a Software Etc(pre-Gamestop rebranding) when Baldurs Gate originally released. As you mentioned, a 5 CD game, one of the biggest game installs I'd ever seen up to that point. Well, apparently the entire first batch of Baldurs Gate that my store received all had defective disk 4s. The install would crap out around 80% or so and not continue.
Sold a shitload of Baldurs Gate the day it released. Within the hour, one guy comes back to exchange it, says he has a defective copy that wont install. Whatever...I give him another one. Then over the next couple of hours a couple more people come back in for exchanges...then more, then the 1st guy who already did 1 echange comes back pretty pissed off. He's probably spent 2-3 hours of his day watching install progress bars at this point.
He wants me to test out another copy in our in-store PC before he takes it home. So I bust one open, start to install it, I think our in-store PC had like a 4x CD rom drive, so it was taking FOREVER. We stood around for like an hour, and sure enough, crapped out on disk 4.
Ended up taking all of our copies back as return and having to send people across the street to Best Buy to purchase it instead. That sucked ass.
2nd most annoying day ever, only behind the Starcraft 1 launch, and every bastard wanted a particular box art(3 different boxes, Protoss, Zerg, Terran). We had no clue that the boxes would be like that before launch, so we didn't know what box to hold for people that pre-ordered it. We ran out of Protoss first, and several people threw massive hissy fits that they didn't get the box they wanted, once they realized they had 3 different options. Star Wars Rebellion also launched that same day, that was a goddamn busy day(even though probably 50% of Rebellions got returned because that game was a bug-filled mess on launch)