Mark has a good post about the new 10g Release 2 version
Marks account of the release is quite interesting as he sees it as I do as not a major upgrade on 10g R1 but in fact a fixing and tweaking exercise. Mark even suggests that some of the new changes may come as patch upgrades to 10g R1.
Mark goes on to talk about the key new features and changes. He talks about the new transparent encryption and key management within the database. Let's hope as Mark suggests that in a later release the key management facilities are expanded. Mark also points out that data in tables that use this feature will be written to backup in an encrypted state.
Mark also talks about the direct SGA access for statistics gathering and then goes on to talk about the coming .NET CLR support in 10g R2 and speculates on the levels of support that are going to be available. Mark's impression is that it will work initially through the EXTPROC features and possibly later be fully integrated in the same way as Java and PL/SQL are supported.
XQuery is also discussed as is the new PL/SQL API for data mining and a few other bits. The interest for me is the encryption, SQA direct access and the .NET CLR being integrated.