But Botman, you can't own CS:S without HL2. Look at the packages.
I looked at the map viewer, and it has a lot more features. It has detail brushes, but I don't know if they are like Quake 2 or Quake 3 detail brushes. It seems to borrow some ideas.
There are also portals now, that can be made to activate when doors open. Sweet!
Also there are displacements, which are used for terrain usually, the standard func_wall (you can use it so vrad casts shadows with it), and some other nifty features. I need to try to figure out how to make a mirror and floors with the specular effect.
There are some good tutorials at
http://www.hl2world.com/bbs/viewforum.php?f=24. They were originally for the leaked beta, but they still work fine.