My Suggestion :
Processor: AMD Athlon 64 X2 5600+ = 4,800
Motherboard: Abit A-N78HD = 4,700
RAM: 2 x 1GB Kingston DDR2 = 1,700
Gfx Card = Zotac GeForce 9500GT-512 MB = 4,200
DVD: LG GSA-H55N = 1,200
= Total Cost (Excluding Moniter, KB, Speakers, PSU and Case) => 16,600. Pretty Much in Budget