As of now, I am happy user of 9.1devel version of PostgreSQL:
=$ psql -c 'select version()' version --------------------------------------------------------------------------------------------------------------------- PostgreSQL 9.1devel ON x86_64-unknown-linux-gnu, compiled BY GCC gcc-4.4.real (Ubuntu 4.4.3-4ubuntu5) 4.4.3, 64-bit (1 ROW)
So, I guess no new features will make it to 9.0 – after all, 9.0 is currently already beta3.
If you want to get list of what I wrote about for 8.5/9.0 – just check the tag page.