The only thing I wish the FZ1 had that the FZ10 has is a manual focus ring. Other than that, I get along just fine with my FZ1 and do not find myself wanting the bigger FZ10, which will also require bigger memory cards, a new case, new add-on lenses and filters, etc. I sure do wish it has a manual focus ring though. I also wouldn't mind the higher frames per second video mode, but that's a luxury. I got used to a manual focus ring on my Sony FD91 with it's stabilized 14x optical zoom! But I love my FZ1, don't mind at all that it's "only" 2 megapixels because with a 12x optical zoom, you're not losing any resolution by having to crop the final picture (like other digicams that may be 5 megapixel, but only have a lowly 3x zoom). Again, you're also able to fit more pictures on a memory card, whereas a 4 megapixel camera is going to require some serious sized memory cards, especially when on vacation and away from a computer.
On the subject of add-on lenses, wouldn't the total zoom be an addition rather than multiplication issue? Remember, any add-on telephoto lens is "seeing" the subject first and not magnifying the subject after the total 12x zoom has been applied. So wouldn't the total zoom be a 13.7x zoom instead of a 20x? Not knowing for sure how to do the math, this seems to be what I'm getting with my 2.5x telephoto add-on (a total of 14.5x). Anyone know how this actually works?