Section one: Builds for non-overclockers
There is a big difference in parts designed for overclocking and parts that well... aren't. There is obviously a price difference, therefore, there is no point in spending extra money on overclocking parts when you aren't an overclocker.
$500 home or budget gaming PC:
CPU:
AMD Athlon 64 X2 5200+ Brisbane 2.7GHz 2 x 512KB L2 Cache Socket AM2 65W Dual-Core Processor
This processor is a dual core 65nm part that that provides superior performance to a similarly priced Intel part straight out of the box. If you're not an overclocker and you're on a budget, AMD is the way to go.
Motherboard:
SAPPHIRE PI-AM2RS780G AM2+/AM2 AMD 780G Micro ATX AMD Motherboard
This is AMD's newly released 780G chipset. It integrates the HD 3200 graphics chip which is the most powerful integrated graphics processor by far which is more than capable of Blu-Ray/HD playback and will help out your CPU a lot during encoding. But that is not the best bit, the HD 3200 is already good enough to do some casual gaming, but it can also be paired using hybrid Crossfire with a HD 3000 series graphics card for almost double the performance. And Sapphire's board is the pick of the 780G's out there.
Memory:
WINTEC AMPX 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory
This is where we can save some money by going for some memory that is perfectly adequate for this build but is not designed for overclocking. DDR2 is at a very low price at the moment so we can afford PC2 6400 RAM. 2x1GB is the sweet spot right now.
PSU:
Antec earthwatts EA430 430W ATX12V v2.0 Power Supply
The PSU is an extremely important part of any computer and should not be ignored or skimped on even when you're on a budget. This power supply will provide sufficient power and there is enough headroom left for upgrading., all at a great price.
Case:
COOLER MASTER Elite 330 RC-330-KKN1-GP Black SECC ATX Mid Tower
This is a case I will often recommend as a cheap but cheerful chassis. It comes with a 120mm exhaust fan but can also accommodate a 120mm intake fan for better airflow and cooling.
HDD: Here the choice is dependant on the user's requirements. If you're not sure where to start. Here are some requirements:
-SATA 3.0GB/s interface. This is the new interface standard and is a lot faster than the older PATA/IDE connection.
-Brand, I recommend either Western Digital, Samsung, or Seagate hard drives.
-Cache, even with a low capacity hard drive, I would recommend at least an 8MB cache.
As for the space, that is entirely dependant on the user's requirements.
Here is just one small suggestion:
Western Digital Caviar SE16 WD2500AAKS 250GB 7200 RPM 16MB Cache SATA 3.0Gb/s Hard Drive
Disk Drive:
SAMSUNG Black 22X DVD+R
You can't really go wrong here but the Samsung drives are known to be reliable. SATA means nice, neat cables.
TOTAL: $338
This isn't mine. I quoted this from the build post by another member. Now, you can spend more on a better graphics card since you already have a copy of Windows. You can get this ATI card
http://www.newegg.com/Product/ProductReview.aspx?Item=N82E16814131088
It's $413.00 right now. But, you get a mail in rebate on the card for $15.00.