Best Professional DSLR Camera, in your opinion?

I'm getting one pretty soon, and I'd like to know other peoples views on a few camera's?

And also, your thought on the Nikon D90?

Best professional DSLR is, without doubt, the Hasselblad H4D-60. But you don't want to know that, even though it's the answer to the question you asked. Because it costs in excess of $30, 000. Yes, that's the correct number of zeros. Like 99% of everyone asking this or similar questions on here, you are misusing or misunderstanding the word 'professional'. What you really want to know is what choice there's in the consumer end of the DSLR market. Here are a few options:
Nikon
Pentax
Canon
Sony

Since you don't give us any idea of your budget, but assuming that it's substantially less than $30, 000, it's not possible to point to any particular model. Go to a proper, physical, hands-on shop and handle a few cameras that are in your price range. The best one is the one you feel most comfortable with. All the manufacturers listed above make good cameras. There's not a lot to choose between them, except how well they handle for you.

From the class of Pro-DSLRs that you are probably talking about it's Nikon D3X!