First one costs £100 less and has a really odd HDD
Second one costs a lot more and includes double the memory, a monitor, an optical drive and a bizarre amount of fans.
Lets start from the start. You are building a PC for gaming and video editing, and you want to fit it in a Bitfenix Prodigy?
If video editing is a priority, and you can afford it, then an i7 is the way to go. If you are struggling to fit it into your build, and video editing is a higher priority than the Prodigy case, then you should consider swapping to the AMD FX8320/8350 and an ATX case.
Now, for gaming, you don't need 16Gb of ram, but if you think you potentially can use it for video editing, then it makes more sense to do it early on an ITX build than any other format, as you only have two ram slots.
The SSD is a luxury, so it might be a good place to save money if you need to. It won't boost gaming performance and there are probably better ways to spend the cash.
As for the HDD, there isn't really a reason to look beyond the Caviar Blue or Barracuda at the 1TB level.
Also, if you are going to get a big front fan for the Prodigy, it's worth considering that the 200mm and 230mm fans are actually quite similar in size (despite how it sounds) as the size isn't the diameter of the fans but a kind of imaginary box surrounding the mounting points. (Can't find a good image of the Bitfenix fans to illustrate, but here's some coolermaster ones http://img689.imageshack.us/img689/6744/cimg0585o.jpg )
I don't know why you would buy 4 120mm fans. It can take two in the roof and one at the back, and it comes with two equipped.