actually the LFP file will be around 20 megabytes on the camera. After processing and encoding it'll probably be much smaller, since it can throw away garbage data and redundant image slices. But megapixels aren't really the right metric anyway.
And the LX5 is good but for my money I'd want a P5000 or XZ-1.
FWIW I have an XZ-1 and it's the single greatest (compact) camera I've ever owned. I can't talk highly enough of it. I sold my 50D w/ 24-105mm f4/L to trade down to something I can daily-carry and while it obviously doesn't completely compete with the SLR, it hasn't left me "wanting" at all.
The XZ-1 looks good, but there's no viewfinder. As a DSLR user who looks to switch to a smaller camera, I'm just not going back to the camera-at-arm's-length-to-view-the-back-LCD thing to take my photos.
The Fuji X100 is the only large-sensor prosumer camera that has a built-in viewfinder (attachable viewfinder is out of the question as it doesn't give you a true enough preview), and so it's the only one I'd be willing to switch to. Come to think of it, the new Sony NEX-5N has an electronic viewfinder that might work, actually.
An attachable electronic viewfinder might work, but then you can't use an external flash together with the viewfinder. Plus, it's just one more accessory you have to buy and carry around with you. Pretty stupid.
And the LX5 is good but for my money I'd want a P5000 or XZ-1.