@mlopinto2k1: layer performance is actually the part that is getting the most overhauling in Gimp 2.7/2.8. On-layer editing, layer groups, GEGL layer management are currently found in Gimp 2.7.0 (the development branch that will end up as Gimp 2.8).
Upcoming work is improved management of vector layers (integration of GSoC 2006 work). Please test and report.
@randomizer: Adobe did port Flash to Linux properly (it's just still flagged as 'alpha'; no more unstable than the Windows, build, that just doesn't say much) - in fact, Linux is the first platform hosting a 64-bit Flash build. what is missing is hardware-accelerated video processing, like on Mac, because no 'open' API exists that can process YUV video in hardware and send it back as RGB to Flash for further processing (adding UI elements, etc.).
Well, that's the excuse anyway (it seems the Gnash developers worked around that limitation somewhat by using an OpenGL backend, but it doesn't fallback easily and isn't exactly geared towards video processing like h.264 decoding, motion compensation and deinterlacing; at least, OGL does take care of YUV->RGB conversion, image stretching and, when shaders are available, postprocessing).