MMO Champion has published yet another graph showing a clear preference in the player population for hybrid classes, which only becomes more pronounced the more group content a player does.
Of course this is only one interpretation of the graph. The raw data says that hybrids tend to have more Valor Points than non-hybrids-- easily explained by their ability to get into group content more easily due to the glut of DPS, as well as the multiple specs meaning there is a use for additional Valor past filling out your main set.
In terms of my own play experience, my tank and healer toons tend to have more Valor points because they tend to be more fun to play for me-- and this is directly related to the fact that I do not have fun waiting between fifteen and thirty minutes to get into the game. I would definitely play my Hunter and my Mage more if this was not the case.
One thing I've never been able to resolve in my head is the idea that the pure DPS classes are anything but horribly unbalanced in their lack of flexibility in grouping. Personally I thought the idea of a hybrid tax was a good one, and necessary to prevent these classes from being undervalued in raids, but Blizzard has since stated that they didn't like this as a solution and have abandoned it in favour of a vague promise of eventually coming up with a way to balance it.
Speaking of the hybrid tax, isn't this identical in concept to what we're apparently getting in 4.3, with melee being deliberately buffed to deal more damage than ranged classes? I'm surprised I haven't heard this referred to as the "ranged tax".