You're in luck! I purchased a computer just last week for this very purpose!
My budget was $1100, and I wanted it for After Effects, Premiere, and Skyrim. Coincidence? I spent about 3 months researching parts and prices, and I finally bought everything with a few discounts and started building it last night! I haven't finished setting everything up yet, but it's all plugged in and everything seemed to be working fine.
After putting everything together last night, here are my thoughts on the build:
- The case is awesome, but slightly smaller than I expected. I had a very scary moment when I thought my ENORMOUS GPU wouldn't fit. It JUST BARELY fits. I also am pretty sure that the fan LEDs don't have an on/off switch, so that could be an issue.
- The cable management was pretty tough with such a small case. I mean, It's an amazing case, but since the PSU is on the bottom, I had to route a few of the cables up and over the CPU right in front of everything since the cables were kinda short.
- I kinda wish I had spent more money on the motherboard. It was nice and cheap, but I found out that it only has USB 3.0 ports on the back, and IT DOESN'T HAVE USB 3.0 INTERNAL HEADERS. This is very important! The Challenger Case has two USB 3.0 front ports that can connect directly to a motherboard via a 19pin cable, but my motherboard doesn't have the required header! So I'm having to buy one of these: Silverstone PCI Express Card with USB 3.0 Internal Connector to be able to use my front ports.
Despite what anyone says, you DEFINITELY want the 16GB of RAM. I've been using After Effects on my Laptop for the past year, and I only have 4GB of RAM on it, and rendering 10 layers of 1080p frames takes forever, and I can only preview-render about 25 frames at a time! The new 16GB that I have is going to be amazing.
Hope this helps you!
EDIT: You might just want to wait til Black Friday. Like I said, I spent 3 months researching these parts and getting super excited, and finally I just broke down and had to buy everything. I just couldn't wait any longer! But I bet you could save somewhere around $100 if you wait til Black Friday, especially since Ivy Bridge is coming out in November and that might make the i5-2500K drop in price.
I'm not too sure on the AMD vs. Nvidia argument. I purchased the 6950 based on a recent Tom's article that said in general, GeForce cards are better for 3D monitors and Radeon cards are better for multi-monitor setups. Since I eventually want 3-monitors, I chose the Radeon.
I'm pretty sure you don't "need" the i7-2600k. Look at all the benchmarks all over the interwebs. The i5-2500k performs just as well (and even better in some CS5 scenarios) as the i7-2600k. A few benchmarks showed the i5-2500k actually outperforming the 2600k when running After Effects CS5. If you want to have the best of the best, sure. Shell out another $100. But everything I've read says that it just gives diminishing returns.
On the other hand, with the Ivy Bridge processors coming out next month, you might be fortunate enough to see a drop in price in the 2500k and the 2600k, so you could decide from there.