In my experience FireWire is much faster then USB 2 even if the specs say that USB 2 is faster.
Also FireWire 800 has been out for about a year now and is twice as fast as the original Firewire so I would expect to start seeing that on camcorders soon.
As far as camcorders go only the 3 CCD ones are going to give you pro results, but they start at about 2k.
I've bought most of my camera gear from these people.
www.bhphotovideo.com