Features.

The Playstation 3 is well worth the price for all the features you get in it. Just a few examples of the features you get are :
-Blu-Ray and DVD player
-Can run Windows XP on it
-Can plug in computer mouse, printer and keyboard
-Bluetooth headsets
-Can charge MP3's, Ipod's etc.
-Can plug in MP3's, Ipod's etc. and listen to music off of them
-256 MB of RAM (Random access memory)

This is amazing considering that the cost is 399$ for a 40 gig and 499$ for an 80 gig. On average a Blu-Ray player costs 250$-400$, so realistically you are only paying a max of around 149$ for a 40 gig and 249$ for an 80 gig (if you are buying a Blu-Ray player anyways.) For what you get with the PS3 I would pay the extra cash to get it. Would you?

PS: Xbox 360 only has DVD. Wii has neither. Ha!