New Equipment Question

I currently have Mac Pro Dual Core 3GHz machine with 6GB RAM

It's six years old and time to move up.

I'm using FCP X and Motion, cutting short promos and narratives, but it's just too slow.

So I'm upgrading to a new system and need opinions on what to get.

Price is an issue, and I don't think I need top of the line everything, but speed is the thing.

Budget is under $4500, including a screen.

I'm thinking the Mac Pro:

> Quad-Core (One 3.2GHz Quad-Core processor)

> 16GB Memory

> 2 1TB Hard Drives (mirrored for events and projects)

$3000

Still need a nice screen. Suggestions?

Should I get a graphic card other than what comes with? For example: ATI Radeon HD 5870 ???

Should I get 12-Core instead of the Quad-Core? (Worth it?)

Anything I'm missing?

Thanks!!!