Scott Long posted the latest FreeBSD release schedule. We will see FreeBSD 6.1 near 20 March 2006 and FreeBSD 5.5 near 3 April 2006. FreeBSD 5.5 will be the last 5.x release, with security fixes continuing through 2007 or perhaps 2008. FreeBSD 7.0 is not planned until some time in 2007.
If you follow the thread from Scott's post, some in the community have problems with the pace of releases. I think expectations were formed with the 4.x tree. FreeBSD 4.0 arrived in March 2000, and the end of the line appeared with FreeBSD 4.11 nearly five years later in January 2005.
In contrast, FreeBSD 5.0 arrived in January 2003, and by April 2006 the 5.x tree will end with 5.5. Given that FreeBSD 5.x wasn't considered STABLE until FreeBSD 5.3 in November 2004, I understand why some people are concerned. I am already using the amd64 port of 6.0 in production, but I have several systems still running 5.4.
Incidentally, within the release thread Peter Jeremy made a stunning comment when someone noted the steps required to implement a security patch:
"Speaking as a developer, I think it's trivially easy.
As an end user, I don't think this is acceptable."
Read the whole post for the context. I was impressed to see a developer put aside his coding hat and look at the world from the end user's perspective.