I called around, trying to find out what it'd take to save the data. The lowest cost quote I could find to even look at the thing was over $250. So I stuck the drive in a drawer to see if inspiration struck later.
A couple weeks ago, my other SATA drive died. (OS is on regular ATA. I've got a lot of disk drives.) At this point, I figured it couldn't be coincidence -- it's much more likely that my motherboard and it's on-board SATA were the culprit.
Tonight, I picked up a external enclosure, that plugs into SATA and turns it into USB. This makes it lose a massive amount of speed (thus rendering it useless for video editing, but fine for storage), but essentially bypasses the board that may or may not have killed the drives. Plugged in more recently dead drive -- works great. Plugged in the more important one (with the wedding vid), it spins up and abruptly halts, then tries again. One might describe the sound as repeated crashing. The computer brings up the other drive almost immediately, but doesn't seem to recognize that this one is even trying.
Anyway, the drive is under warranty and I can get Seagate to replace it, but the data is forfeit. I'd REALLY like to not lose this data -- I know what it's like to have your wedding videographer friend flake out on you, and I DO NOT want to be on the other end of that exchange. My buddy trusted me, and I don't want to have betrayed that trust. (and yes, the original source tapes are gone. I didn't think I'd lose everything to a hard drive crash.)
So...Does anybody have any suggestions for cost-effective data retreival?