What are you going to edit?
The i7 with 16Gig has a 5400 rpm hard drive, which is below specification
The i5 with 12Gig at least has a 7200 rpm hard drive... but only one, which is also below specification
You need a 2nd 7200 rpm hard drive for project and video files... anything else, especially with HiDef files, will be very slow
I've just parchased a DSLR and plan on working with HD video along with big files (RAW). I'll be editing video from that and it's mostly personal use. The RAW files I'll be using Lightroom and Photoshop and that eventually will be for professional use. I could get a seond hard drive as you mentioned.
So I need to look for desktops with at least a 7200 rpm hardrive right?
Right now my system is over 6 years old and and here is the graphics card that I currently have http://www.newegg.com/Product/Product.aspx?Item=N82E16814161252. Opening up Photshop is slooow.
I'm on a budget and I want to keep it under $1000.
With that budget, you may want to consider Premiere Elements and Photoshop Elements. A less powerful computer is needed than with the Pro versions.