Steinberg says they have a "Christmas gift for all of our Cubase SX3 customers": the free 3.01 update announced today
includes a new RoomWorks reverb. It's surround-capable, "studio-class,"
includes 60+ presets, and scales CPU usage to your machine and project

Many minor updates, too, some that will make a big difference — the
MIDI device panels system now controls effects and not just instruments
and a 'ping' can be used to measure processing delay of any external
effect for automatic delay compensation. That's external as in hardware
effects, adding to existing delay compensation features. (Apple's
Logic, by comparison, still lacks automatic delay compensation, and
while SONAR and MOTU DP have automatic compensation Cubase is the first
app I know of that will work with external effects.)

Download from Steinberg's Web site.