When I bought the FZ20, Canon only had the S1 out which was 3.2 mp and I was upgrading from a 3 mp Olympus 3x optical zoom. I liked Canon because you used AA batteries but wanted more than the 3 mp. So when Panasonic came out with the FZ20 with 5 mp in July 04, I waited patiently for the reviews and bought one in Sept 04.
Canon S2 IS came out 4/05, S3 IS in Feb 06, and now currently has the S5.
Panasonic is or has just released an 18x optical zoom, 8 mp but there still isn't a full review for it. I'm considering upgrading to get more zoom and am trying to decide between the ultrazoom or dSLR? I like having the zoom and other features built in to the camera vs changing lenses and carrying more stuff.