Yeah, I love SSDs myself and OWC has gotten a fair amount of my business. Haven't outfitted anything since the PCIe cards came out. I've got one of the New 480s laying around here somewhere (I lost a 240 for 3 months once), but I just don't have time to slap it in, it's going to replace the older version in there now and that one's heading for a laptop.
Did you consider any other video card? I'm debating what to get now, but after reading the latest BareFeats tests, it looks like every card has its strengths and weakness. I've had the 5870 for a while, but it never seems to be working all that hard. Now that the New MacPro won't allow upgrades, all of a sudden there are lots of GPU choices.
Sounds like we're doing some of the same stuff, I get carried away on smart objects myself, although I'm pretty sure I don't have any 20Gig files.
I'll probably throw some upgrades in the Old Hex after the New MacPro comes out and I figure out if I want one or not.