If you have a Mac, you should check out
dead.licious, a little desktop application that searches through your del.icio.us bookmarks for dead links and then shows them to you. It said I'd be able to edit the bookmarks through the app, and I couldn't, but it was still really easy then just to search my del.icio.us for the faulty bookmarks and put in the new URLs I'd googled.
So, my del.icio.us is now officially 100% not-dead. :)
I should, of course, give props to
Lifehacker for the link.