Even though I have a reputation as a "web 2.0 guru" in certain circles (or at least I think I do) there always seem to be web 2.0 applications I'm slow to adopt. Case in point, del.icio.us. Del.icio.us is a social bookmarking site, and let me tell you, it is genius. Not only can you save links and access them anywhere, but you can sort them, tag them, and even share them. I only started using it the other week, and I can't believe I didn't use it sooner. If you haven't tried it yet, I highly recommend you do.
P.S. Want to see what I'm looking at lately? Check out my bookmarks.