Firstly, some of the advice you're getting on this forum is very dumb. If you want a good rendering workstation on a budget, go with an Intel chip, amd is better for almost everything these days but you'll get excellent performance rendering with a dual-core Intel Pentium 4 at a decent price, considering its usage. Secondly, ignore the people telling you to get a gaming video card and low latency ram, they havent got a clue how rendering works. Gaming cards are designed structurally for the sole purpose of rendering images as fast as possible asyncrhonously on the fly. They are not designed to render high quality models and images synchronously such as a rendering workstation does. Dont waste your money on a gaming card, you can get several times better rendering performance on a budget workstation card (I'd recommended Matrox if you arent planning on using SLI as their business is completely dedicated to rendering workstation cards) than you would with the top of the line gaming card. Quadro's are just modified Geforce cores. Imagine a rendering card as a work horse and a gaming card as a race horse. A race horse might be alot faster in a race, such as gaming, but it would be a weakling when it came to the duties of a workhorse. Likewise a workhorse is powerful but it would be very slow in a race against race horses. Also with Intel you can use higher bandwidth ram which is WAY better for rendering because it requires massive bandwidth, timings are NOT important in rendering. If possible go for the highest bandwidth DDR or DD2 ram that the motherboard allows (again I'd go with Intel simply because they move bandwidth faster in 3d rendering and alot of rendering software are being optimized for hyperthreading right now) Whoever suggested using low latency ram on a single Opteron 265 is obviously poorly educated and spends too much time on here trying to figure out how to overclock his budget system that he saved 3 years of allowance for so he can play counter-strike all day in his parents den.
Opterons with the "2xx" rating are specifically for dual CPU systems, and are the same speed as a "1xx" rated opteron. A 265 and a 165 Opteron are exactly the same speed and same chip, the only difference is the 265 has been certified for dual cpu usage and thus costs more.
Go with these specs
*Dual-core Pentium 4
*motherboard with whatever features you will use (SLI is a good idea) and that supports DDR2 ram if possible
*High bandwidth ram
*SATA2 HD if possible, and RAID is probably a good idea incase something bad happens and you lose weeks worth of rendering
*Budget workstation card (Either a Quadro for SLI if you have more cash later and want to easily ratchet up your rendering speed or you can get a decent Matrox card that will match or beat a single Quadra for much less money)
*A good PSU, at least 450watts if you plan on using SLI
And whowever told you that you need an LCD screen for 3d rendering needs to have his head examined. You wont get an appreciation for the color depth on an LCD screen and most people that view your work will be looking at it on a CRT screen as they know better than to use an LCD to begin with when working with 3d rendering and graphics design.