My first DSLR Camera, general advise please?

I was looking at cameras like:
Canon 1000D,
Canon 550D,
Nikon D3100,
Nikon D7000

I'm gonna use the camera mostly for Bmx photos and other action photos.
Looking to keep the price below R10 000
If you have advise for me it would be nice if you can help me out
Not really sure if a flash is needed for specific photos so please give advise on that 2
Was looking at "Nikon Speed-Light SB600"

Well my first dslr was the nikon d3000 which I bought last year. It's very good and easy to use for beginners. So I'm sure the nikon d3100 would be similar.

For action photography go for the one that can give you the highest burst rate. You will need also to select a good lens to go with the camera (a fast lens).

You can leave the flash for later and invest on a good quality lens as a priority.

Nikon D3100 14.2MP
http://www.amazon.com/...ag=0891-20

Technical Details
14.2-megapixel DX-format CMOS image sensor; 3-inch monitor with One-Touch Live View shooting and movie capture
Includes 3x 18-55mm Zoom-NIKKOR VR Image Stabilization lens
Full 1080p HD Cinematic Video with full-time autofocus and sound
Easy-To-Use Nikon Guide Mode with intuitive controls and on-board assistance

Well for what you wanna do the nikon d7000 is perfect. It can take up to 6 pictures a second which is twice the d3100/3000.plus it's ISO range is 100 to 6400 (expandable to 25, 600!). With this range you can take pictures in really low light and even at 6400 it has very little noise. If you have no idea what I mean by ISO just trust me, it's good (my nikon d70 only goes from 200 to 1600). You should look it up for a detailed explanation.
The nikon sb600 speedlight is a very good first flash.decently powerful and lightweight. It can also be used as a wireless flash. But if you want to use it wirelessly you would have to either buy a su800 comander or another flash that can control flashes like the sb700 because the d7000 doesn't have commander mode on it's on-camera flash. I would suggest getting the sb700 AND a sb600. Then you would be able to have one flash on camera controlling the 600 while also flashing. You would already be set for future flashes too. I've found that an extra flash would be handy because I just have an sb600. (just so you know, you don't need a flash to take bmx pictures.actually if you used one they would probably be worse. I highly recommend at LEAST getting a sb600 because it's helpful to have for any occasion)
if you get this kit I guarantee you that you'll be able to do what you want and MORE rather than with the d3100/3000.plus the d7000 has HD video!

good luck!

and if you want photography tips visit this site: www.digital-photography-school.com

and please check out my photos: www.flickr.com/drashpics