Given this I don't understand why people are recommending an AM2+ system.
I can put together an AM3 system with 4Gb DDR3 for less than those listed above...
If you're dead set against against an X3, put an 810 in instead, these all clock as high as a 940 anyway. You don't need 8Gb RAM now, and when you do DDR3 will be even cheaper.
Monitor choice is yours... the psu is as good as it gets + modular for a clean install. The WD Green drive was my choice for quietness, you may want different, I simply put down the same graphics card as everyone else.
No one's mentioned you might want a decent cpu cooler, budget £30 for a Sunbeam CCF, TRUE or Scythe Ninja as examples.