I have written more than a couple of times of the ills of using matrix or evaluative metering along with TTL flash. Personally my opinion is that these "innovations" no matter how wondrous are more trouble and more work than they are worth. This has nothing to do with me not understanding how the controls and camera work. Of course they are useful in situations where you really really have to be quick and you have no time to think and you have to get the shot and you've only got one shot at it.
The reality is if you are taking the time to place more than one light or even one light with ambient by definition you are not in that situation. Manual control is quicker, it's easier, it gives you more consistent shot to shot results and you will get exactly what you want. Instead of railing against that today (well I guess I just did) I wanted to post a 30 second exercise that I just did with my auto everything DSLR and point out some things if you insist on wrestling against the computer in your camera with the "quick and easy way".
For these I used two flashes on TTL w/ compensation controlled wirelessly via a D200 in commander mode. The shot at the top is just ambient metered the way I would probably do this kind of thing in a pinch, it actually retains good atmosphere - I would just stick a person in it and make sure the wonderful window light was hitting them the way I wanted it to. If I had to retain detail in the room and the background I guess you have to do flash or some nutty HDR stuff.
Here is matrix metering alone.
Here is on camera TTL flash - cool we have a perfect exposure that looks like absolute shit. If this is how you use your flash I would suggest getting a hammer and breaking it your images will thank you.
Okay - now we need detail in the room and the background but I want a similar sense of atmosphere that we had without the strobes. What do we do? Well as best we can we try to mimic what the natural light is doing and reproduce it's direction as much as possible - from the back with front shadows that are just a higher value. Okay step one put a flash behind the flowers and backlight them, let it do double duty and put some light on the ceiling as well but we need to block it from the wall the windows are on with a handy dandy magazine scrim. Turn it up a notch to give it some direction. Step two fill in the shadows with soft light that mimics the way the ambient light is working. Move it around until the relationships are similar to the shot at the top of the post. Okay now we have a little bit to dark in just a couple of areas - turn the on camera flash on and way way down so it doesn't cast it's own shadows Crap it is reflecting in the window - change position a bit so the reflection is somewhat hidden by overlapping it with a natural highlight.
There we have it - quick and easy matrix adjusted TTL powered PIA IR remote that won't let you place the lights exactly where you want them wonderfulness.
Ps. The lesson was try to emulate what you like in natural lighting conditions no matter what lights you use. Seriously. Oh and the corollary was to not worry too much the background let it go white it is rarely important anyway. Make a conscious decision on what you are photographing and what detail adds to the image - Some of the best photographs do not have detail everywhere - in fact most of them don't.