The CALEA mandate is yet another in a long list of privacy violations. Francisco Franco would be proud of the US.
The research shows that if the tapping capability is there, law enforcement will use it. i.e. although mobile/cell phones *can* be tapped, landlines are favoured for tapping by ratio of something greater than 10:1 (I don't remember anything more accurate, but you get the idea).
While the likelihood of somebody else tapping your Internet traffic may be low, the probability is never nill.
Now that all compliant ISPs have the taps in place, the number of capable ISP employees that can run a tap has very likely increased while the effort in making a tap has decreased. So, if you look at a tap-capable ISP employee as a commodity to be bribed, the market just became more accessible through competition. As a consequence it more likely that, say, a group of private investigators, previously unable to afford the resource, now could.
Of course, if you're not cheating on your wife, you won't have as much to worry about. But suppose you're email address is in the address book of someone who is, rightfully or wrongfully, being investigated for a criminal offence...
Recap: The more available this resource is for *someone*, the more available it is for *anyone*, and the more it gets used anyway.
Obligatory bow of the head: I, for one, welcome our new overlords.
If you don't want to bow your head, it's not obligatory. I often use Relakks, an anonymous IP provider in Sweden. I am not an employee or agent of Relakks (I'm not even a Swede), but I find the service well worth the 5 Euro/month despite the, naturally, slightly slower connection, which is 1) a PPTP VPN tunnel 2) through Sweden.