Hey, a good way to include all necessary exposures from the vast majority of rooms/windows would be to set your bracketing at -1 0 +1 and start with the highest bracket at the bottom of your meter (for the highlights). (Basically you have the other two stops out of view of the meter display). After those three exposures have been taken you will have -4 -3 and -2. Then you can start your next three exposures at -1. After that you will have -1 0 +1. Then move up to start at +2 for another three exposures for all your shadow detail. After that you will have -4 -3 -2 -1 0 +1 +2 +3 +4
This is still a quick way of gathering all the necessary exposures for a really smooth HDR. The only problem being the time between moving the brackets could cause motion artifacts and similar probs. I find Photoshop makes great use of all the available information if you merge in there (of course taking the step back in history palette to get rid of the 32bit preview option) and send to Photomatix for the final tonemapping.
I'd say there's no best pre-defined settings, as always in photography.
The only advice I can give for HDR is that you check the histogram and be sure to cover the both dark and bright zones when you make the bracket. That way you can never be wrong!
I also guess that the 5 shots bracket using a 2ev difference should be good enough to cover most situations.
As others already said, if the scene has super high contrasts then 5 pictures with -4/-2/0/+2/+4 could be necessary, but if the light is quite even then 3 shots with -1/0/+1 could be enough. However I often prefer to shoot using a 2ev difference to make sure I get more details in lights and shadows.
