Change the case maybe a CM 690/Centurion. If money is no issue Antec 900 runs well although be sure to grab a modular PSU since that cable management is pesky. I'm going to grab a CM 690 soon to replace my NZXT lexa blackline.
Chuck in a better PSU since antec is aimed at the low ends - Your PC certainly isn't low end mid end = corsair, maybe a nice Seasonic (heck there all the same company just different ends of the market) S12/M12 series modular are very nice.
Check for an 8800GTS should run cooler and OC better at that res. Very nice monitor by the way going to order it next week when i get paid .
Be sure to grap a nice cpu cooler, perhaps a TRUE if your willing to spend the $.