PC under $400

Hey Man!
Im addicted to gaming and system building but I don't have the "wawart" (money) to indulged my fat ass on a pc shopping bliss where everything you use is all highend and fast, and shiny, and hardcore, and extreme, and......haaayyy!(bubble popping)! Back to reality, I need a fix, and of course a budget fix. I prepared some list of budget build that can be decent on any games, and be fast on multimedia and any office application except 3D rendering. The list was for the CPU only, just add the monitor and all the peripherals of your choice.

AMD build*
Processor-------------Sempron 3400+ ($70)
Motherboard ---------WinFast K8M890M2MA, integrated graphics ($55)
Memory--------------2x 512 MB DDR2 SDRAM -667 ($68)
Hard Drive------------Western_Digital WD1600JS, 160 GB, SATA/300 ($55)
Optical Drive----------Samsung SH-S182D ($30)
Case-------------------Any ($30)
Power Supply---------Coolmax ATX Black 400 W ($27)
Total Cost-------------$335

Intel build*
Processor-------------Celeron D 352 ($56)
Motherboard---------Asus P5LD2-VM ($95), integrated graphics
Memory--------------2x 512 MB DDR2-667 ($68)
Hard Drive-----------Western Digital WD1600JS, 160 GB, SATA/300 ($55)
Optical Drive---------Samsung SH-S182D ($30)
Case------------------Any ($30)
Power Supply---------Coolmax ATX Black 400 W ($27)
Total Cost-------------$361
(*prices varies on online shopping)

Both are clearly capable of handling any office and multimedia task and the level of performance provided by the budget processors still is acceptable. The hard drive is fast enough to make the system feel quick, and 1 GB of RAM is enough for applications to run smoothly. And both systems can be upgraded with dual-core or Multi-core processors in case you are not happy with the performance after a while.
But, I wanna play Oblivion! Call of Duty4 or Crysis even!

Here is my alternative list*:
Processor---------------Pentium Dual Core E2180 2.0Ghz. ($72)
Motherboard-----------ECS 945GCT-M2 ($43)
Memory----------------Team Elite 2x 512MB DDR2-667 ($35)
Hard Drive-------------Seagate Barracuda, 160GB, SATA ($55)
Graphics Card----------Palit NVidia 8600GT 512MB ($67)
Case with a 500W Generic PSU ($36)
Total Cost---------------$308.00
*based on Iloilo City Philippines prices

Sacrificing the optical drive and a good PSU resulted a more playable system,
of course adding a good PSU will be over $400.

HEC is the only brand you can actually see on display on various computer shops here in Iloilo.
So buying it will be my suggestion if you are an Ilonggo or you can buy online.

This specs can play Oblivion with all the sliders maxed at resolution 1280x1024, AA 0, AF none
with a playable an average 25fps Outdoor.
Call of Duty 4 and Crysis can be smooth on medium settings. Higher than that, crappy.

Conclusion:
So these are the options you can have on building a budget PC, of course you can try different products/brand of your choice. My choice is based on my experience on building computer systems here in Iloilo for people who don't know much about P.C.s. Overclocking may improve the performance of these specs, but it would be risky and may need additional peripherals basing on our hot and humid climate.