From the look of your setup I'd definitely invest in a good quality t.v. unit or alternatively have one made to the size and specs you want and get safety glass with magnetic locks for the doors - that'll keep the buggers out. I made up a unit out of pine reasonable cheaply (see pic below) and must say it's very satisfying seeing them pawing at the glass trying to get at the goodies inside.

Try to integrate your front speakers into the t.v. unit - free-standing speakers and speaker cables are like a magnet to crawling kids. Rear speakers should be wall mounted high up out of arms reach with all cabling either hidden inside trunking or, even better, inside the wall. Remember, what they can't see they can't pull.
I will say though that NOTHING will prevent them from drawing on your t.v. My new Bravia lasted exactly 4 days before my 3 year old decided to trace Winnie the Pooh permanently onto it in blue biro. She actually did quite a good job too so despite my initial stress levels hitting an all-time high I was secretly quite impressed with her penmanship...
I guess it all goes with the job of being a Daddy... so enjoy and remember when they do break something it's not the end of the world (plus it gives you a good excuse to upgrade).