If you're curious as to what the innards of the PlayStation 3
slim looks like, iFixIt has all the gory pictures
for you. They go through a step by step process of taking the machine apart and have some pretty nice pictures to boot. I think the mainboard looks rather elegant and it's cool to see what all goes into the machine.
The one thing that the Sony console gets right above the other two is that the power supply is internal where as the Xbox 360 and Wii have bricks attached. In fact, I'm really impressed Sony was able to build the slim with the power supply still inside and keep the relatively small form factor.