Your thoughts on free / open / public databases in chemistry

Antony Williams, Request for Input from the Community – Public Chemistry Databases, ChemSpider Blog, October 25, 2007.  Excerpt:

I will be writing an article in the next couple of months regarding the value of Public Chemistry Databases. I am going to write this article with a bias towards databases with “structure intelligence” – databases where chemical structures form a part of the accessible content.

Rich Apodaca has already blogged about  Thirty Two Free Chemistry Databases and of course I will be reviewing many of these. There are others that have popped up since Rich posted.

I am interested in your suggestions of online chemistry resources that you use and that you find of value….