Advice on components to build 3ds max workstation

I've been trying to decide what components to build my new system around. I run 3ds max, VRay, Vue, Afterburn, FumeFX. In combination, these really stress my current system (Q9550 on Asus P5wdg2ws pro, 8g ram, quadro fx 4500, 300g velociraptor and a few other drives for storage and running sims). My goal for this system is to significantly reduce sim and render time. I like the quadro card, so I'll likely go with another that fits my budget ($2,500 for entire system)...I was thinking the Quadro 2000 is probably about the right amount for my budget.

The choices for mobo/cpu are my main concern - there a so many choices, and I want to get as much performance per dollar as possible. I've been looking at sites where you configure your pc online, and it seems in my price range I could go with an i7, or dual opterons, or dual xeons. So, I'm looking for some advice on what would be most suitable for these applications. There are likely other options worth considering too.

I'm not set on hard drive(s) either, but I'm a little more comfortable making a decision, but I'd like to hear what others may have to say about their experience, and get their advice.

Regarding power supply, I like the modular ones because that makes cable management a little easier, and I'm guessing around 850w should be sufficient.

Memory...I guess that will depend upon the mainboard choice? I'm hoping to get about 24g though.

I haven't started looking at cases yet, and cooling will depend on cpu, so I'll research that after choosing a cpu.

Thanks in advance for taking time to respond...