Looks like it's time to drag out the old sensor size chart. Apologies to the regulars who are sick of seeing it.
NewEnglandCamper, some quick background would be helpful. Point-n-shoots are all terrible at fast shots in low light. This is just the way it is. Spending more is no guarantee of better results, a $200 Fuji F40 will beat a $500 big-zoom from anyone in low-light performance (except certain other Fujis.) The reason is that, to make the cameras so small, the sensor that captures the image has to be very small. (This is also part of the reason why cell phone photos look so terrible! Their sensors are
really puny!) These small sensors are being asked to churn out a huge amount of data, meaning that each pixel is incredibly small.
"Pixel density" refers to how many pixels are crammed into a certain amount of space. If you have two cameras that a 5mp and one has a large sensor, it will have a lower pixel density and probably better image quality. If you have two cameras with the same size sensor and one is 5mp and one is 8mp, the 5mp will have lower pixel density and probably better image quality.
The reason DSLRs are so much better in low light is because their sensors are
much larger - around 15x larger than the sensor found in the vast majority of point-n-shoots.
Most PnSs have a 1/2.5" sensor, as seen in the lower right. Some have slightly larger sensors, the usual champs in this regard are the Fujis that have the "SuperCCD HR" sensors, that are 1/1.7" or 1/1.6".
Now, consider that most DSLRs have similar or just slightly higher megapixel counts as point-n-shoots, despite a much larger sensor, and you can see why DSLRs have such an advantage.
For reference, Olympus and Panasonic DSLRs use the 4/3rd sensor, all other DSLRs (except a couple very expensive "full frame" ones) use the APS sensor.
Entry-level DSLRs can be had for surprisingly cheap, under $500 now, but are bigger and heavier and to get the best results, you want multiple lenses. (And they don't take video, most don't let you compose a photo with the LCD, etc.)