I use a 2GB card and a Kingston CF adapter. When I bought the stuff 2 years ago, my research at the time had uncovered several sources that claimed it could only handle up to 2GB. Unfortunately, I don't recall the sources - but google is your friend

My only problem is with MP3 audio books. Occasionally when I start the car, the audio book just starts playing from the begining instead of where I left off last time. I happens about 1 out of 10 times. Pretty annoying.

-dan