I agree with almost all of the above suggestions, but no one has yet chimed in to say that one of the best upgardes you can do is to add phono. Get something like a Rega Planar 3 with a Grado or Sumiko Blue Point. It will KILL you Micromega. Even more than speaker placement, vibration isolation, and acoustic treatment of your room, adding vinyl will be a gestalt. You may have forgotten (or, perhaps more likely, never known) how good records are.
Best upgrade for the money ?
My system is currently comprised of a Sim Audio integrated amplifier, Micromega Stage 2 CD player, and Polk speakers. I'd like to improve the overall sound of my system but don't know where to start. I have good not great interconnects - Wireworld. My speaker cable is MIT(again better than average). I'm using the power cords that came with my equipment. Can anyone suggest where my money might best be spent to upgrade my system. I guess what I'm asking is what would have the most impact for say 500 - 700 dollars. Tweaks, better interconnects, higher end power cords? Any and all input would be helpful. Thanks - Rob