Chiming in on this thread, generally... I agree that there's no way you can take a long-term job working for a company which you feel is evil, for whatever that term happens to mean to you. Of course, you can pick any given company, and no two people will agree on whether or not they're evil.

Furthermore, there's a world of difference between taking a full-time job and doing a short-term consulting gig, much less the specifics of the job. If you were, say, an air conditioner repairman and the Scientologists had a broken A/C unit, you wouldn't feel quite as bad about going in and fixing their A/C as you might feel about, say, designing their latest marketing campaign.

(At one extreme end, I know a lawyer who defended the Scientologists in several lawsuits. He was emphatically not a Scientologist, but felt that they deserved capable representation as much as anybody else.)