The STR-DA3600ES is a nice step up from the 2010.  Sony's 3600 adds Digital Cinema Auto Calibration (DCAC) with Automatic Phase Matching.  It also includes a total of four HDMI 1.4 outputs, an on-screen interface for main and secondary zone controls and less than one percent total harmonic distortion.  You'll be able to pick it up for $1,100.

Things get really interesting with the STR-DA4600ES, which incorporates the ability to create not only a second audio zone, but a second zone for video as well.  An HDMI cable will carry audio while a CAT5 cable carries the video signal, which can be upscaled up to 1080i.  The 4600 launches next month at a price of $1,500.

The STR-DA5600ES is at the top of the ES line.  It adds features like H.A.T.S. clock synchronization for HDMI and DSD as well as DCAC EX Speaker Auto-Calbiration, which includes Speaker Relocation.  It can also be used as a DNLA compliant music server to stream audio to clients.  You'll find the 5600 at a price of $2,000. No matter which receiver you pick though, you won't be able to find it online.  The ES line is exclusive to specialty AV retailers and custom installers only.