If you're going for the under-$800 crowd, I don't think I'd change a single thing. The very best CPU and GPU available for such a build, a nicely-featured motherboard, plenty of RAM, a SOLD power supply (Seasonic is great), plenty of storage in one of the better-rated HDDs around, and a case. I don't pass judgment on others' choice in cases, though I don't think I'd buy that particular one myself. Still, Antec makes solid cases. The only thing that's missing is an SSD, and that'd totally blow your budget. Maybe down the road you'd want one, but otherwise, wow. Good choices all around.
Welcome to TR, btw.
I do not understand what I do. For what I want to do I do not do, but what I hate I do.
I control the groove