I've been using delicious2Safari for a while now, and it's a really nice (and free) way to integrate your carefully tagged folksonomies from del.icio.us into your Safari bookmarks.
Combine that with Safari Stand, which makes an extremely useful bookmarks search utility only an F4 away, and I've got a very handy offline cache of del.icio.us bookmarks.
I've also got a shortcut in the Sogudi extension to Safari, so all I have to do when I'm online is enter "del whatevertagiwant" in the location bar of Safari, and BOOM - my del.icio.us bookmarks with that tag.
Very handy loose integration of small pieces.