Subversion 1.5 has arrived: http://blogs.open.collab.net/svn/2008/06/subversion-150.html.

TortoiseSVN 1.5 is not yet released, but has reached RC3 status. I tried it and must admit there are quite some improvements to note. There is also a beta of VisualSVN 1.5 (also for the server).

You can get the binaries, and read more about the new features here:

Edit: In the mean time, both TortoiseSVN and VisualSVN have released 1.5 final