The problem is that when the manufacturers are adding megapixels, they're still being captured by a sensor that's that same size. If you have a sensor that's the size of your thumbnail and you try to squeeze out an extra few million pixels, you have to expect that you're not going to magically be able to coax out much more detail past a certain point. You will also find more image noise as the megapixel count goes up, which is murder on low-light photos.
Plus, you have to remember that photography is nothing but capturing light, and the smaller the sensor, the less light it absorbs, and it's more difficult for it to work well in low-light situations. This is part of what drives folks to use DSLRs - my wife has a Canon SD600 pocket camera and I have a DSLR, both are 6 megapixels, but the sensor in my camera is about 15 times larger. Guess which takes a sharper photo and works better at night?
Megapixels are almost completely marketing-driven. It's unlikely that an 8mp point-n-shoot camera is going to capture much more detail than a 5mp one. And a 6mp camera with a larger sensor will probably give you a better picture than an 8mp one with a smaller sensor. Also, a larger sensor will be able to handle higher ISO levels much better.
The Fujis generally have larger sensors, hence their superior sharpness and noise levels compared to most others, like the S3, H5, etc. Some of the others do have larger sensors (like the Canon A6xx and G-series) but many don't. But like Yekcim said, they lack image stabilization. Most also only use xD cards, which are harder to find and more expensive than SD cards, but the new models take both (finally!).
