I've been going to multi-day music events so mp3 format lets me record more or less nonstop for the whole weekend. My buying criterion was 30 hours of recording, which would fit in 2gb, but I went for the 4gb card since I figured I'd always want more capacity and I didn't expect flash prices to come down this quickly (the ipod nano had caused a temporary shortage). Meanwhile, 8gb cards are available and 16gb cards have been announced. I guess with a 16gb card (plus my existing 4gb) I could do a whole 30 hours in 44/16 WAV.