There will be always someone who develops a GPU miner for any coin and GPU mining is always going to be more profitable.
It's still more-less OK to CPU-mine cryptonotes (Monero and clones) IMHO.
Late to this thread, but thats not true for Gridcoin, because the work are real scientific research problems, general purpose CPUs will always be needed. Though some problems can be CPU accellerated they always need a CPU co-processor.