Hi Chip, thanks for the reply.
Here is some more info about my shots. I was using the central AF point for metering, not the automatic selection (maybe this was my mistake?). Most of the times locking the focus on my subject first, and then recomposing. Flash was never used in any of the photos.
Here are some examples along with the meta data. Notice the faces on the portrait photos, and the too-bright white sky on the landscapes.
Picasa Web Albums - stojmir - Too sunny Autumn
I guess next time I should pay more attention to the histograms.