I've been screaming this for forever...
"D&D has grown further away from its roots with every edition." Eventually I had to take a stand and stick to 3.5. While it has lost much of what made me fall in love with the game when I first played AD&D, I feel it has a good enough balance of new fantasy and old atmosphere.
What I feel is most lost is the feeling of fear. The fear of traps, the fear of the monsters, and the fear that your character could die tonight. I believe this article sums it up best.