I was asked a question about my shooting Auto-ISO so I thought I would answer it here as well.
"My question is have you ever tried auto-iso? If so I have read by a few others in reviews that it selects a really high ISO even if you have a external TTL flash. Which would leave the image overexposed."
I do use Auto-ISO on both my D700 and D7000 in certain situations. Leaving the setting stock out-of-the-box is going to give you issue, so change them.
Here is what I do:
Set my Base ISO (normal every day setting) to the lowest setting; for the D700 it is 200 and the D7000 it is 100.
I shot a couple of images at the higher ISO ranges (like 800 - 1600) and find what my top limit is that I am willing to accept. I set the Maximum ISO to this setting. (typically 800-1000)
Depending on the action going on (basketball, rodeo, etc) and the lens I am using, I will select the minimum shutter speed I will accept. Typically this is 1/250sec.
Now that I have my settings in the system – I just go out and shoot. The system will always use the lowest ISO to achieve the correct exposure based on all my OTHER settings. (ie Shutter/Aperture Priority, EV etc) This includes when using flash. What needs to be taken into consideration is the EV setting on the flash will also affect what ISO the system selects.