Game consoles should freeze only very very rarely. The argument that computers freeze often is invalid. The reason computers freeze so often is because of all the software we juggle around and all the junk we put into the operating system. It's because every PC is different in some way. There are thousands, if not millions of possible hardware combinations between video cards, sound cards, processors, memory brands, motherboards, and then there's all the different drivers to run on all these.
This is why Macs rarely freeze. Their system is so proprietary that they don't have to worry about all that many hardware combinations. But the downside is more expensive hardware, and less options due to it's proprietary nature. (which is why I stick with PC)
This is also why game consoles up until now rarely freeze. The software only has to work on ONE combination of hardware. Of course now there are two possible PS3 hardware combinations, but as far as the games are concerned, both are identical.
The freezing seems to be due to the fact that we are now at a point where processing power is so high that the units are now much more sensitive to heat buildup.
I have a Wii and a PS3 which have never locked on me. They are both in the open, and my apartment is nice and cool inside, with the temperature rarely exceeding 70. And so, for those of you experiencing lockup problems, I'd recommend first ensuring that the vents on the sides are not obstructed. Next, ensure that they aren't in an enclosed cabinet. Finally, what is the temperature in your gaming room?
If all these check out, then you probably do have a defective system. But if you're running your Wii/PS3 inside an enclosed cabinet, what do you expect? Either install some fans on the cabinet to circulate the air, or move the systems out in the open. And if your room is heating up, try to find a way to get the temperature back down.