I have all of those things listed under the "current set up:"
The current parts such as you listed in the quote above are fairly easy and I assume others following this thread looking to "upgrade" would have them laying around or in there current builds as well
I wouldn't spend $200 on an AMD CPU & motherboard though. Sandy bridge looks pretty promising given the price.
I'd look for a deal on 8GB DDR3 RAM (~$65), a sandy bridge combo (~$110+), and a nice graphics card. Tigerdirect had a GTX 480 for $230 after rebates last week. Remember the prices I provided are pretty much the cheapest you can find right now (with rebates).