The goal of Snow Leopard will be to enhance the performance of OS X, not provide new features.

From Apple Insider:

Specifically, Snow Leopard will be optimized for multi-core processors, tap into the vast computing power of graphic processing units (GPUs), enable breakthrough amounts of RAM and feature a new, modern media platform with QuickTime X. Snow Leopard will also include out-of-the-box support for Microsoft Exchange 2007 and is scheduled to ship in about a year.

Snow Leopard will also raise the software limit on system memory up to a theoretical 16TB of RAM

16 TB of RAM!

Read the entire article here. [appleinsider.com]