Which one dslr camera is best for beginners?

With price not exceed than $600.

There isn't just "one".

Any entry level DSLR made by Nikon, Canon, Pentax, or Sony will do. Prices are similar and within your budget.

Comparisons, reivews and prices here: http://www.dpreview.com/...CompactSLR

They call them "entry level" cameras for a reason. B K gave you the best advice.

Canon, Nikon, Pentax etc. They are all good and you should pick the one that you feel most comfortable with.

I got my nikon d3100 single lens kit for 600 and that included insurance for 3 year + a free photobook + 100 standard photos for 3 years
An i love it is a perfect camera to start out with, it is not difficult to use and it has crystal clear picture if you don't move to much or when it is mounted on a tripod

This is a nice question in every photography beginner mind. There are many good entry level camera, best I prefer is Canon EOS series.