Get a Canon Powershot ELPH. they take great quality stills (for a point and shoot) and they have a night mode on them,
although for any night pictures you'll need a tripod, it doesn't matter, it just takes more light to make an exposure, so it takes more time, and the camera needs to be steady. You can change the ISO to a higher number, and it will let you take a quicker picture (faster shutter speed) but its going ot be way more grainy.
Invest in a tripod for your night shots, they are like $30
The powershot's also take pretty decent video.
I recommend the SD750, it has a large screen on the back (2.5 or 3 inch) 7.1MP and is really small and nice looking
. it is a slightly older model, so its alot cheaper now, but i still love the quality and the looks.
http://www.amazon.com/Canon-PowerSho...5463507&sr=8-1
if you still wanna spend a little more money, the SD890 is new, and is $399
I love my powershot SD400 for point and shoot, its small and i can take it anywhere.
I break out the Rebel XTi for my serious stuff though
*EDIT* If you want something with changable lenses, you're going to need to spend more money. the Canon Rebels are a great place to start with an SLR camera.