If its entertainment your after I would highly suggest the antics in the "electric blanket" thread.
Highly entertaining, and from what I'm led to believe, quite healthy too.
Seriously though, I went with a rechargeable dock from JB hifi.
Does around 15-20 hours before needing a recharge.
Quite small but loud and clear enough for our purposes.
I paid $120 for it. Of course a week later they were on special for $90........
We were going to install a stereo in our hawk, but decided it would be a pain while the kids were watching DVD's and someone would always lose out.
By having a portable dock we can put our music on a table away from their noise........
JKB obviously knows what its like.............
Love the kids dearly, but theres only so many times you can listen to their stuff.
Cheers
Brian