Switch the Seagate for a Samsung Spinpoint F3. It's an all around better drive at the same price. It might not be in stock when you need to order, so I'd look around other suppliers, or go ahead with the Seagate (it's a nice substitute, but just not as good).
That burner is an IDE model. You defiinitely want a SATA one. It'll only a be a couple of bucks more.
I highly recommend getting different RAM. Corsair is a lot more expensive than other. My favorite is G.Skill Eco 1333mhz CAS Latency 7. It's $2 more, but a lot better.
For your resolution, I would get an HD 5770. It's newer, more future proof with DirectX 11 support and almost as powerful. It's also a lot cooler and uses less power, making it much better in Crossfire. You won't be hurt with your resolution, but if you do upgrade your monitor later, you should get a second one.
Total with my changes: $655 (with Seagate, $665 with Samsung F3) without shipping, before rebates. Might be a bit above your limit, but I think the changes are worth it. Don't forget the Bing cashback (I don't know what percentage it's at, but 1% would be back under budget).