I've been using del.icio.us for quite a while. My links are here:
I just used it earlier today to remember a page I found that can create pdfs online - I had a publisher file I needed to view but I didn't have publisher installed and didn't want to download the huge trial version just to get a printable copy.
Another site I bookmarked a while ago that I like and mean to look at more frequently than I do is "the librarian without walls" Marylaine Block's "Neat New stuff". It brings me back to the days of Yahoo magazine and the joy of discovering new stuff I didn't know I needed - I love serendipty and often feel there's not nearly enough of it online....