Because you're using your PC for CPU- and RAM-intensive work as well as gaming, your needs will be different from someone who just wants to play games. Thankfully, you seem to have the budget to match those needs. Here's what I'd recommend:
...which should bring you to a little over $1200 before shipping.
"'Casual games' are something the 'Game Industry' invented to explain away the Wii success instead of actually listening or looking at what Nintendo did. There is no 'casual strategy' from Nintendo. 'Accessible strategy', yes, but ‘casual gamers’ is just the 'Game Industry''s polite way of saying what they feel: 'retarded gamers'."
-Sean Malstrom