Canon 40D or Nikon D90?

Hey guys! :)
Well, lately I've been searching for a DSLR camera and I'm having trouble with deciding which one to buy. I'm a student and therefor I don't have a big budget, so I'm looking for the best camera I can buy In a low price. As you can see I narrowd down my search to 2 cameras:
Canon 40D & Nikon D90..

I want to know which one of the cameras is better? and what lens is the best for me?
I'm not a begginer but I'm not a professional either. I want to get sharp photos with vivid colors. Also, I want a lens that works good at night & with low-light. Generally I prefer a lens that works pretty good with all kinds of shooting, but slightly better with portraits and macro.

I hope the information I gave about my needs will help you to answer me.
Thank you.

As you need good low light ability you should go for the Nikon D90.

- The D90 goes up to a maximum of 6400 ISO with 3200 ISO being very usable (it's the same sensor and image processor as the Nikon D300 that I have).

- The Canon 40D is previous generation technology and only goes up to 3200 ISO. It's a more pro-level body with up to 6 frames/second but you haven't said you need that.

Nikon also has the advantage in lenses with the best bang-for-the-buck:

- the 35mm f1.8 is cheap and a good walk-around low-light standard lens (no Canon equivalent)
- the 50mm f1.8 is a cheap low-light telephoto
- if you want a really versatile lens usable in low light then the 18-105VR is supposed to be really good (and cheap - it's almost given away in the D90 kit). It isn't really a low-light lens (maximum aperture f3.5-5.6) but the VR (vibration reduction) helps you to get a sharp picture at slow shutter speeds - as long as the subject isn't moving. (No direct equivalent from Canon)

There are lots of other lenses possible (second-hand 85mm f1.8, 18-200VR..) but they are all more expensive.

Low light isn't my first priority, but it is quit important to me.
Which lens will be cheap and good for macro/portraits? :)

Thank you so much!!

I'm not a big macro fan. By "macro" we mean something really small like insects or jewelry. The 50mm won't focus that close. You really want a 60mm or a 90mm macro lens, but they aren't cheap..