Anyone have any recommendations for symbol sets usable in AutoCAD?

Let me add some extra info/background. I'm a Civil Designer by trade and spend all day in AutoCAD '07, '09, Civil 3D '07, & '09. I haven't used it much to do gaming maps since the results are so antiseptic (by intentional design). However, Autodesk recently released a pretty cool program called Impressions that takes DWG files and add a great deal of artistic flair. For examples, check out this gallery. So, with this new capability plus an increased amount of online gaming (Play by Post) time have enticed me to start using my professional skills a bit more for my gaming maps. I am hunting for block libraries and such to help out. Any ideas?