I think it's time to put this baby to bed.
SongsWithoutWhich has been a lot of fun, a lot of frustration and a lot of inadvertent discoveries for me, but it's run its course. I think that anyone who can find more than 500 songs -- and I haven't; we're into the mid-300s here -- that they can't live without is probably spreading their jam a little too thinly on the toast.
And when I have to spend time actively looking through my archived tapes and lists for songs that I might have overlooked, rather than have songs just arrive in my head, then it's time to call it quits.
I hope you've enjoyed the ride.