Hello,
I am building a desktop computer for 3D modeling. The applications that I will be using are Blender, LMMS, and Audacity. My hardware is as following:

AMD Phenom x6 3.0ghz
ATI Radeon HD 4850
Western Digital Black Caviar
4gb Corsair DDR3 Memory
Asus Motherboard

I have been using Linux for awhile now and I am not afraid to use the command line. I am wanting a distro that is stable and fast, which lead me to Slackware and Debian. I just don't know which one to choose. I have used Slackware in the past, and I was quite impressed with the speed and stability. However, as Debian is also known for those same qualities I don't want to pass up a choice distro because of a lack of familiarity. I need a distro that will recognize all 6 cores ( I will be rendering a lot), and one that has fairly good support for the graphics card ( as in drivers). I would greatly appreciate any opinions, especially from anyone who has used both of these distros.

Thanks.

In terms of usability and speed, there should be not much difference between Slackware and Debian. Both of them will support your CPU and graphics-card (I would go for the proprietary drivers for your card for performance), so there should be no problems at all.
If you already are familiar with Slackware I would recommend to go for that, so that you can concentrate on the things you want to do, instead of learning a different distro.

1 members found this post helpful.

Well I was hoping for a few more opinions, but I think that you have said everything that needs to be said.
Thank you.