Your best bet is to find something with your base requirements and something that allows you to have manual settings so you can take what you learn and apply that to the night shots and fireworks.
A great, comparison research site is
DPReview which allows you to compare and contrast features, price and sometimes has hands-on user reviews.
I went to WDW back in May and rocked two point and shoots, both Canon, the
Digital Elph and an older
A530. I really like the "color highlight" feature on the Canon, wherein everything is Monochrome except one color in the camera. Here's an example:
Personally, I stick with Canon or Nikon. They make excellent pro-level cameras and are on the cutting edge of image processing, giving people what they want - low noise and higher ISOs.
So after a quick glimpse of what is out there, I'd be buying one of these four: Canon Powershot G10, Nikon Coolpix P6000, Canon Powershot SX1 IS and Nikon Coolpix P80.
Comparison of the Four.
But i cannot stress this enough, to get the shots you want, you have to learn how to use it. The biggest problem most P&S cameras have (beyond low light problems) is shutter lag, meaning how long it takes for the camera to take the picture from the time you push the button. This is something you have to learn to compensate for so you can get that peak shot.
Example:
Now for fireworks, you will probably be limited to 15 seconds max for an exposure, which is completely fine. 5-10 is all you'll need. However, most P&S will do post processing for the same length of time of the picture you just took if you took a picture that goes longer than 1 second.
So this 5 second shot of illuminations took another 5 seconds before i could shoot again.
So again I'll reitterate to everyone out there who actually reads what i have to say - I mean i do this for a living and i really hate to see people spend thousands of dollars to try and get pictures and walk away unsatisfied - You can get great photos with the camera you already own. You don't need to go out and drop 700-3000 dollars on a dSLR to get amazing pictures, like this lightning shot (15 seconds, f/8, set on a trashcan and angled up with the edge of my baseball hat)
Just learn the basics and spend some money on a basic book, rather than a $1000 dollar dSLR.
