Try this on for size... it's based on a build I'm putting together.
Proc: AMD Athlon 64 X2 3800+ 1GHz FSB 2 x 512KB L2 Cache Socket 939 Dual Core Processor
Mobo: ABIT AN8 Socket 939 NVIDIA nForce4 ATX AMD Motherboard
RAM: CORSAIR ValueSelect 1GB 184-Pin DDR SDRAM Unbuffered DDR 400 (PC 3200)
Vid Card: XFX Geforce 6800GS PVT42GUAD7
Case: I-STAR Nitro AX S-10000S Silver Computer Case
NeoHE 500 ATX12V 500W Power Supply
HD (Storage, Internal): Western Digital Caviar SE 250GB 3.5" SATA 3.0Gb/s
Optical Drive: PLEXTOR Black IDE Slot Load DVD Burner Model PX-716AL/SW
Total ~ 1100. (Excluding S&H, and taxes)
Now, if you need to shave a little bit off to fit that into your budget (or to afford a new monitor, etc), you could easily find a cheaper case (this is the case I fell in love with), smaller HD (I'm a movie junkie, so I need the space), and/or buy a no name DVD drive (for like $40). doing all that could easily drop the price of this rig to below $1000, giving you room to buy a monitor and speakers for your budget.