Hardware acceleration and plans for GIMP 2.8, GIMP 2.10, GIMP 3.0
As to read on gimp.org and in the feature roadmap, these are the plans for the next GIMP versions:
GIMP 2.8 will contain single-window mode and layer groups, planned for late 2011/early 2012.
There are some Google Summer of Code 2011 projects that are already in progress but they won’t be available in GIMP 2.8 yet because time is too short for integrating. GIMP 2.10 will contain these projects and further cleanups in the source code.
This will allow GIMP 3.0 to switch to GEGL and bring hardware acceleration using OpenCL (multi-core and GPU support).
Also, from GIMP 2.10 on shorter development cycles are planned so that new GIMP versions will be released more often.