Unless you want to go to one of the high end Computer "Boutiques" like Velocity Micro, Alienware, Digital Storm, Falcon Northwest, Maingear and Origin PC. , look at the pre-builts that Newegg offers. http://www.newegg.com/Desktop-PCs/Category/ID-228
iBuyPower is know for using retail components to assemble their builds. So, upgrading them in the future should be no issue if you shop wisely.