I can't tell you much about anything else, but I would go for the Athlon. They're cheaper, their motherboards are better, and they are more effective. Intel is more raw power, but they're over the top pricewise, for me.
For monitor, on two computers I have Samsung Syncmaster 955DF (flat screen 19") and they are wonderful. Good tech support, and I can smack them as much as I want while I'm playin' BG2, and they take it.
