It depends on if you are going to overclock. If not, then just go with stock cooling (air). If you want to OC mildly, then go for some nice aftermarket cooling options (still air). If you want to OC like a mad man and squeeze every penny out of your hardware, then go for a nice water setup (it's well worth the $$ IMO).
Cases? Eh, I honestly don't care as long as they look good but thats just me
Like ^ said, wait untill the new amd cpu's come out (hopefully soon) or if you can't wait go for a C2D.
Memory cooling I've never had to worry about so can't help ya there