Hard Disk Drive
The most significant difference is that the current model of Playstation 3 has twice as much disk space. This is important for users who plan to download large quantities of games and movies.
Physical Shape
The 160GB PS3 Model uses the "PS3 Slim " architecture introduced in 2009. It is almost 33 percent thinner and 36 percent lighter than the older version, and its chipset uses less electrical power. The rear power switch is absent on the PS3 Slim, and the front eject and power buttons are no longer pressure-sensitive, instead operating like regular buttons. However, both systems can play all the same games, movies and discs
Linux Support
Support for Linux and other secondary operating systems was removed from the PS3 Slim. However, users who want that feature can still find it in the old 80GB model.
HDTV Interface Compatibility
Unlike the 80GB PS3, the 160GB PS3 has the added compatibility with Sony HDTVs. The PS3's Cross-Media-Bar (XMB ) interface can be controlled with the HDTV remote, and both the PS3 and the HDTV can be turned off simultaneously.
Features Missing From Both
The 80GB and 160GB PS3s are both later models, so they lack some of the features found in the early 2006--2007 hardware. Neither is capable of playing Playstation2 games, and neither has support for flash card readers. Both the 80GB and 160GB PS3s have only 2 USB ports as well (instead of the four ports seen on early PS3s ).
Conclusion
If price is an issue, a used 80GB PS3 can be acquired cheaper than a new 160GB PS3 Slim. But with the exception of Linux support (a feature that most users will not miss ), the 160GB is clearly superior for its larger hard disk and more intuitive aesthetic.