Here is a picture of Samsung LTM201U1 20" S-PVA panel (Dell 2007fp v2) taken from a 5 degree angle (from center) by Peter G at Digital photography review:
Is this related with the alignment and movement of the liquid crystals in the cells ? Liquid crystals in VA matrices are not perfectly straight and they have slight problems with the colour rendering from a 0 degree angle (and as the consequence you will not see the all colour details properly). More interesting thing is that in order to see the problematic part of the image properly, you have to move your head slightly off axis as the direct focus in front is no joy. It's not newly developed phenomenon, as I witnessed this live on couple of occasions when observing the Samsung PVA panels.
For now, only S-IPS panels variants have almost perfect "perpendicular" alignment of the liquid crystals (at any state) in the cells and they can offer true and wide viewing angles with excellent picture uniformity across the panel.
Tamlin has the point here. Manufacturers, especially Samsung, are usually overrating the viewing angles specs (they are definitely everything else but not honest) and issue from the above is usually not so frequently mentioned ... and if you have the good eyesight you will spot it by yourself, no doubt. We have the situation that with some screens, image change is present even with slight viewing angle change (5 degrees or so) ... in essence when looking straight on the panel. Monitor spec on the paper (especially if it's not honest) is one thing, but real life experience is another.
For me, viewing angles and picture uniformity are very important and I would not sacrifice them in favour for any other fancy feature. Industry should review the standards for viewing angles and maybe more importantly review the manufacturers specification norm.