Generally speaking, a "professional" camera has interchangeable lenses.
There's also a tradeoff between price and low-light quality. The better the light performance, the more expensive the lens and CMOS/CCD chipset.
I've never found a professional video camera for less than $5k, and most of what I like is $10k+ up into the $20k range. These days, most of what I shoot is done from Nikon DSLRs, for short-term bursts. Eventually, I want to upgrade, but it's unclear if I'll ever be able to afford one of the truly nice professional cameras. I don't shoot video for a living -- that's one of the few video aspects I reserve purely for fun and hobby.
The Sony HXR-NX5U NXCAM is from Q1 2009, almost 3.5 years ago. For HD video cameras, that's a bit old.
Cameras like these are more like advanced camcorders, similar to how a $500-1000 DSLR is an upgrade for a point-and-shoot. Nice serious hobby cameras, but you'll end up in a bind for professional work use, as it's sure to disappoint under several common lighting situations.
I read about some Canon cameras that came out in late 2001 and/or early 2012, but don't recall the models offhand. I pulled the articles, but they're in a big box of unsorted research materials. (I'll be sorting them in July sometime.)