I have a few observations here.
Are you looking to add more hardware, another graphics card perhaps? The Antec Earthwatts 500W is a highly rated PSU (reviews by JonnyGuru and Hardware Secrets), I would not be looking to replace it unless it's broke or you have a need for more power (Or perhaps if you really don't like the "generic" look of the PSU).
As far as cases, I usually will not go into specific recommendations since case preference is a personal thing but I will recommend you look at the CoolerMaster "HAF" (High Air Flow) cases as an option.
Hope I helped some.
After reading your comment I do realise I won't need to upgrade my PSU really. I won't be looking forward to have a SLI setup and new graphics card are getting more and more efficient. Thanks for the help.