If macro is a BIG part of what you need to do, then a point and shoot is probably a better option than the Rebel.
Because of the small size of the sensor in a P&S camera you get much greater depth of focus. I have an EOS 5D MK II with a fill 35mm size sensor and a 180mm Macro lens. While the quality of the images are good, very little is in focus at and one time. Either the near part is or the middle. Even with a very small aperture the DOF is small. The Rebel sensor is not as big, but it's bigger than a point and shoot camera and will suffer the same shallow DOF but to a lesser degree.
Shallow DOF is great for portraits, but I hate it on macros

There are ways around with but it's a pain.
I often find myself using my old Casio Exilim EX-1000 for macro. Everything is in focus with that.
P&S cameras though are generally rubbish at night photography. The small sensor that helps with macro makes low light photography grainy. The 5D MK II on the other hand is one of the best low light digital cameras around at the moment.
You seem to want two opposing things from one camera. I don't think you will ever get one that does both things superbly.
I say, decide which is most important to you and get the best for THAT job.