Once I pick a card, I'd definitely need help choosing a reliable PSU since I know that purchase is probably going to outlive the card. As for cases, HDD, and memory, I'm not too concerned about those as those aren't as difficult to choose.
So, you`re getting the 480? It`s a good choice for the money. Enjoy!
Concerning the other components, that seasonic PSU is peace of mind really. Again, good choice.
Couple months ago I bought a Corsair 500R case, really nice case. I have two other Antecs and this Corsair is simply much better than either of those. Newegg has posted several video preview for cases which you may find useful.
For HDD, look into a SSD for your Windows install and HDD for storage, game installs ,etc. SSD`s have seen a decent price drop lately and you`ll like how your new machine is very responsive. I am using a Samsung SSD in this computer but do have Crucial M4`s in two others.
Finally, considering memory 8GB 2x4GB 1600 1.5v should do it. 4GB minimum
Just my 2 cents...