My DVD player really heats up discs? ?

I have the same player and experience. For what it's worth, I shipped the player to Sony to address this issue and was told it was normal. I don't know if this is an honest assessment or a stonewall.

If you "Freeze" your player prior to use the discs will not warm up! Sorry I couldn't resist as there has been a big Freeze on everything thread reply as of lately ;0)~

So next to having Sub-Zero design your Home Theater room, your warmth issue is a Sony Dvd player normal occurance.

Now if it's melting your Dvd's then it's time to take repair action!

Good Luck

Try Movie Titles such as "Smila's Sense of Snow", or "Ice Age" see if they run cooler??? Oh I'm sorry there I go again......... Gotta get back to squeezing my 42" Plasma in a body bag, then in the Frigidaire ;0)~

Jer:
If it's a ventilation issue you can temporarily place the player outside its current location and see if the heating degree is less.
Half an inch is not that much in my opinion. What's above and below the player in the rack?

Well it does not sound like a ventilation issue but I have it on the next level above my amp and 2 inches above the amp and 2 inchs above the s9000es. It could be better ventilation but it could be a lot worse.
I am tempted to see how it operates with the case removed. I could just blow out any dust accumulation every couple of weeks.

My Philips DVD963SA does the same thing and there is plenty of ventilation around it (4" on either side and more than 1" on top)...redbook cd's even get mighty warm...I was expecting to see that you owned the same player when I clicked on the thread...seeing that you have a player from an entirely different manufacturer leads me to believe that this is not completely out of the norm.