Raw cores are the way to go for pure render. AMD has the lead right now on cores-per-dollar,...but Intel's new Sandy Bridge is
still too much for it. The Phenom II X6 beat the 2500K in
exactly one test (multithreaded POV-Ray 3D rendering). In all other tests, the 2500K absolutely
crushes the 6-core Phenom, even though it only has 4 cores. Yes, it's that good.
So here's the recommendations.
CPU -
2500K ($225) Best bang-for-buck on the market right now, bar none. Comes with HSF, easy overclock to 4GHz just by turning it up.
MLB - GIGABYTE
GA-Z68MX-UD2H-B3 ($170) - MicroATX Z68-based board with lotsa hookups for expansion and upgrades later.
RAM -
F3-10666CL9D-8GBRL ($80)
HDD - Your choice ($90)
OS - I still prefer
Win7 x64 Pro ($140) over the
Home Premium ($100) version, but it is really a personal choice (and Home Premium
is always upgradeable to Pro later)
Total: About $650-700 (depending on OS choice) without tax.
What's that? I left out the GPU? Yep. I did that on purpose. With the Z68 motherboard, you'll be able to use the integrated Intel graphics processor that's right onboard the 2500K CPU. It will be pretty slow compared to your (unreliable) 9800GTX, but it will also consume a lot less power (putting less strain on your 500W PSU) and you sound like you won't be using the system for any kind of serious gaming anyway. The fact that the board is MicroATX will give you additional power savings, making your smallish PSU last even longer.
Also, you'll be able to use
Quick Sync for ridiculously fast transcoding. Rowr.
--Patrick