I wouldn't touch a Core2Duo. It's on a dead socket right now. You don't really save anything over an AM3/DDR3 build, and you lose any opportunity to upgrade.
I'd look into the Athlon II X2 240 and a cheap AM3 (NOT AM3/AM2+) board. Get a 2x1 GB kit of any cheap CAS Latency 7 RAM, preferrably 1333 mhz or higher.
I wouldn't get anything under either the Samsung Spinpoint F3 500 GB or Seagate 7200.12 500 GB HDD.
For the PSU, get a nice 450W Corsair or Antec unit.
Tack on the cheapest SATA DVD burner you can find.
You will not be able to play any games with just onboard graphics. You will need a discrete GPU for gaming. I'm not to sure on prices over there, but try to get an HD 48xx series, or if you can stretch it, an HD 5770. Check out this article for a ranking of GPUs by price and by power (the hierarchy chart). Get the most powerful one you can afford.
I dont need ddr3 coz its not available at my place, and dont need a high end psu those things are not avil here ,U know if once i went to a retailer and ask abt antec and Some coolermaster case fans ,He said it is not available here and they said coolermaster is the best PSU manufacturer n the world!