Which of these cameras are the best?

Okay so quick:
I'm buying a camera for my digital photography class at school. It needs to be a SLR that can save. Raw Images! Woohoo! Okay!
So I need to save money so I'm between two cameras (used):
-Nikon D3000
with 18-55mm Nikkor Zoom Lens
Used $197 or $225 (for a more mint condition)

OR
-Canon EOS Digital Rebel
with Canon 18-55mm EF-S Lens
$169

OR

-Nikon D40x
with Nikon 18-55mm Lens
$225

The D3000 is superior to the D40x.

There are so many digital Rebels, that it is impossible to tell which one you are thinking about. If the Rebel is more than 10MP, newer than 2010, or have video and/or live view, that would probably be my pick over the Nikon. Otherwise, get the D3000

If I was starting out and wanted to keep the camera for a long time I'd go with the D3000. Go for the newer one if possible as it likely has less shutter activations.

But for a photography student they're all pretty equal.

The specs you mentioned are of Canon T3i and T3i is better than other two cameras which are mentioned by you. T3i is a 18 MP CMOS Digital SLR Camera and DIGIC 4 Imaging with EF-S 18-55mm f/3.5-5.6 IS Lens
Here is what professionals say about T3i, i hope it will aid your decision:

http://www.amazon.com/...9N74Y83IH/

If we compare D3000 with Canon T3i, we can see that T3i has more upgraded features which will definitely shoot better snaps, here is a brief comparison for you:

T3i Shoots Full HD (1080p) video as well as still pictures while D3000 doesn't have this feature.
T3i has 1, 040k dots resolution screen while D3000 has 230k
T3i has a feature of live view which Preview your photos on the camera's screen before taking them
T3i has Lower noise at high ISO, 793 ISO
Canon 3i has a flip out screens option too which can be helpful when composing tricky shots or taking movies.
It has a Has a CMOS-family sensor while D3000 has a CCD sensor
T3i has a built in focus motor but D3000 doenst have one.
T3i has Better maximum light sensitivity with 6400 ISO and 12800 boost ISO