God Brought Baal-Worship On Himself
Don at the Evangelical Ecologist reminds me that the suffering of the plagues was not just visited upon the people of Egypt (who, under the organicist theory popular among terrorists and people fighting against terrorists, are arguably punishable for their leaders' sins), but also on their morally innnocent livestock. Don suggests that we could see this as God making a point against idolatry. He points out that animals and anthropomorphic deities were popular at the time -- witness the animal-headed Egyptian gods and the Israelites' own Golden Calf. So smiting a bunch of animals was God's way of saying "I am more powerful than any animal, so worship me, not them."
I'm not sure about the specific concern with animal worship, but I think Don is right to see the larger picture of the Plagues as being a case where God manufactured an opportunity to make a demonstration of his power, thereby cowing the Israelites into worshipping him.
Reading the rest of the Old Testament, it's clear that God's Shock and Awe strategy failed. The OT is a litany of time after time when the Israelites turn to idolatry (worshipping the Caananite gods Baal and Asherah), and God is forced to do some smiting to keep them in line. And in any event, the Plagues even failed to convert the Egyptains. But I think we can go farther than just saying that smiting is an ineffective deterrent -- I think it's also partly responsible for the temptation that Baal posed to the Israelites.
With the Plagues (and earlier nefarious acts like the Flood), God established a certain frame for choosing deities. That frame is one based on power. Worship the God who can smite your enemies, and who will smite you if you give up on him. God isn't making a moral plea ("worship me because I deserve it and because my decrees are just"). He's making a pragmatic demand ("worship me or you'll end up with boils or worse"). God sets himself up not as an altruist who wants what's best for his creation, but as a dictator who demands obeisance and will sacrifice his creation to get it.
But with this power-based frame in place, it's no wonder the Israelites kept turning to Baal. In the long run, God is more powerful than Baal and will engage in more thorough smiting. But Baal offered a great deal of more immediate power, both supernatural and socio-political. The benefits of Baal-worship were thus clear, whereas there was little other reason to stay loyal to God.
*It occurs to me that there's a parallel here with the way Pilate wanted to let Jesus go, but the crowd badgered him into signing off on the crucufixion. So perhaps the New Testament God is a bit Satanic as well. This is why I have trouble with the idea of seeing the crucifixion as a sacrifice demanded by God.