What is a decent desktop for around 600$?

i am looking to buy a decent desktop im mainly going to use it for gaming but i honestly dont need a gaming machine my price range is going to be around 650$ what is a decent kinda everyday use desktop for around my price range im going to upgrade the ram and graphics card to make it better on gaming but all i play is world of warcraft half life and rift so i dont need a b *** computer im looking to buy the desktop its self for around maybe 550$ the other 100$ is going towards a monitor and a decent graphics card