Well as far as the case goes, I'd say it's pretty cool. I have the X-Predator white edition and I've quite enjoyed it. The biggest downfall about it is how large it is, it's just a little inconvenient to move around but overall it hasn't bothered me much. One thing strange about it is there is no reset button but that hasn't really bothered me either. Anyway, if you want a case with plenty of space than this definitely offers it, and I like the visual design of it. It's not low key but not over the top. I find it's just right.
8gb of ram is perfectly adequate. I don't really see why more would be needed except for the most extreme user.
For me 500gb hdd is extremely small. I have two 3TB hdds and a 128gb ssd. I find the two 3TB are comfortable for me, I have a LOT of videos on there but I can see that perhaps in year I will want another HDD. The ssd is my first and it was a serious increase in performance, it definitely makes general use a LOT less frustrating. I found 128gb is pretty good for me, I have a number of applications on it, downloads, entire music library, bunch of pics, operating system and there's about 45gb left.
I can't comment on the processor as I'm more familiar with Intel however it seems as though while AMD is cheaper and from what I've found, an intel 4 core i7 is about as good or better than an 8 core amd the amd still seems to get the job done pretty well, depending on the model of course.
When comparing amd and nvidia cards 2 years ago, I found amd got better framerates for the price but Nvidia had physx. Pretty sure that video card is the second top amd card out at the moment so there shouldn't be any problems in terms of performance.
I agree the power supply seems a little overkill. I know that an equivelant current series Nvidia card would need about a 500 watt power supply. I don't know how different this would be for you though.