I keep a few PDL factoids handy just in case our pastor decides to try that route. Thankfully, we are in a year-long study of the book of Revelation

and are just now in the middle of the second chapter, so that won't be coming up for a while, if ever. One site that I would counter Warren's pastors.com with is 9marks.org, which has had a
few things to say about PDL.
My Mother in Law read The Purpose Driven Life while she was lost in the Catholic church and developed a hunger for more protestant teaching, which made more sense than the works related faith she had understood all of her life. That led her to attend church with us, and she has grown beyond the teachings of Warren. For that reason, I try to be gentle. I do, however, see it only as a beginning step for someone to attend a church that does not share its teaching.
PDL is similar to the rags that cushioned Jeremiah's arms, while the sturdy rope pulled him from the well. Once the salvation is found in the real support, the rags can be discarded. I don't see it as a positive thing, mind you, but a good pastor can help someone remove the chaff from the wheat.
To throw some fuel to the fire, did anyone out there realize that Warren studied under Robert Schuller?
The Purpose Driven Life by Rick Warren - "The Bible says, 'He rules everything and is everywhere and is in everything.'"
Hour of Power (November 9, 2003) by Robert Schuller - "Yes, God is alive and He is in every single human being!"
Prescriptions for Living by Bernie Siegel - "God is in everyone and everything."