Started about a week ago, almost exclusively CPU mining since I'm running mostly low-end nVidia and a get more from the CPUs than the GPUs.  That said, I'm just setting up a couple 6970 rigs and am in the process of optimizing.  I've got a few questions but haven't hit the newbie threshold to post any questions in the relevant mining threads.  Only a couple more to go!  Currently mining at 500-800 MH/s.