As per your request, here's what I'd build for your situation (common productivity + light-moderate gaming), with parts linked from US Newegg so that you know exactly what to look out for:
CPU: AMD Athlon II X3 435
Motherboard: ASUS M4A77TD
Video Card: Sapphire Radeon 4850 512MB
Case: Cooler Master Centurion 5
RAM: Any 4GB (2x 2GB) DDR3-1333 or higher, e.g. this one by G.Skill
HDD: Samsung Spinpoint F3 500GB or Western Digital Caviar Blue 500GB (whichever is cheaper)
DVD Drive: Samsung DVD Burner
Power Supply: Corsair 450VX
OS: 64-Bit Windows 7 Home Premium OEM
Please let me know if you have any questions!
"'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
Essay Pro