1 TB Western Digital HDD salvageable?

I apologize in advance for my verbosity.
About a week ago I went to dinner as I would on any other day. Came home to watch some television I'd downloaded and I couldn't access my hard drive (I access it wirelessly via my Airport Extreme wireless base station, connected with USB 2.0). Froze up my Mac, which seemed like it was having issues as well. Had to relaunch finder and tried again. Nothing. Long story short, after directly connecting via both firewire and USB, repairing permissions (with Disk Utility) on my internal HDD, scanning it for problems, I narrowed it down to problems with my external drive. Had it almost a year; not making any clicks or awful noises. Not dropped, etc. It was almost full (about 50 GB left when it fritzed out), and so was my internal, but I cleared a bunch of space off of them. The external can't be that fragmented, as I just use it for mass storage, not a lot of writing and rewriting to it. Scanned with DiskWarrior as well, and everything says there are no discrepancies or problems with the drive. I can still see the file structure, and browse through the folders, but it might take a few minutes to display their contents. I opened up an mp3 after about... 5 minutes and successfully transferred a word document to my computer that opened. Nothing else could be opened.
Almost a week later, I'm still flummoxed. Downloaded SuperDuper (recommended by a friend) to do a backup to my new HDD, and it took three days to backup all 900GB. Finished this afternoon, and only about 250 GB was actually transferred, and that was only bits and pieces of tons of my files.
I'd noticed Spotlight was constantly trying to index the drive after it mounted and figured that might have been causing problems, but i disabled it and it didn't change anything. After the unsuccessful three day backup, I tried again (as if something had changed) to manually drag and drop the files to my new drive. The most common error messages I get are that the file is in use (when it obviously is not); that the file ".DS_Store" is in use or having problems; and Error -36, that it could not be read or written. The .DS_Store file is kind of like the desktop.ini on PC, and I wonder if it's just a communication problem with my Mac (between the two), but I upgraded to Snow Leopard and figured maybe that should have fixed it, but I don't want to go deleting system files. There are no issues with the new drive, and I'm just wondering what could have happened in the one hour or so that I went to dinner that would've caused my drive to have such problems. Neither fragmentation nor the drive being full, nor anything else I can think of would cause sudden incapacity. There are no sounds to indicate a hardware failure either, as it can (eventually, usually) read the data on the drive. I can preview it, get information about it, but opening it to read it doesn't work. I'd also think if there were bad sectors, it would show up on any number of the scans I did, and that those scans would have taken much longer, but they didn't.
Only thing I can think of that MAYBE would have caused problems is a lightning storm earlier in the day. I wasn't home, but was near my house and lightning struck. It's extremely doubtful it struck my house, but if it did, would a power surge have caused a head crash or something similar??? Regardless, none of my other electronic equipment is damaged, and it's all plugged into grounded outlets, etc...
What could possibly be going on to allow me to SEE my data and look at stuff ABOUT it, but be able to retrieve none of it? Please help!
I'm hoping there's some chance I can salvage it. I don't care if the backup takes a week, I need stuff on there. DiskWarrior is supposed to be the hero of failing drives, and it rebuilt the directory multiple times with no errors and still nothing. I don't want to erase the drive until I know beyond any shadow of a doubt that my data is lost and gone forever.