There are TONS of free sites out there for us to store bookmarks. I've tried many of them over the years: Delicious, iKeepBookmarks, Live Binders, etc.
I find it's easier to save the sites to a bookmarking site, that I know we will be using in the lab. This way, the students can find it a lot easier and are not required to type in long URL's.
Below are some of the professional and personal bookmarking sites that I have either used in the past, or am currently using:
Live Binder: Computer Lab
Live Binder: For Teachers and Parents