You might not want to hear this, but your machine isn't that bad off. Coming from 2 285's in SLI, you'd have to spend the money for 2x 480's to beat your current setup. And that will be at least $800, probably more like $900.
On your HDD's, you have dual vRaptors. Going from that to an SSD might give you some increases, but it won't be by a large margin and it won't be cheap also.
In the end, you'll be spending over $1000 for very moderate to negligible increases. Not to mention, unless you are running 3 monitors at full resolution each, there won't be any game where you will see a big difference in performance with. I guess the biggest thing you would get from going from GTX285s to GTX480s is tesselation and DX11. Both of which aren't widespread yet, but growing.
If I was you, I honestly would wait. Wait until 2011 when Nvidia releases 'Fermi2' which should be based off the awesome GTX460 design. Also, SSD tech will have even more time to evolve, become cheaper, and faster. I feel like you will be much more satisfied from your purchase then.
Of course, if you really feel like dumping money, then go for the upgrades. Asus Ares. Check it out.