Remember to take in account other applications running on the same server; for example, repository browsers use resources too, independently of Subversion itself. It comes with a command-line client that uses them.In general, you can expect to need much less server memory than you would for comparable CVS repositories. There are two different Subversion server processes: either svnserve, which is small standalone program similar to cvs pserver, or Apache httpd-2.0 using a special mod_dav_svn module.If you want to host a networked repository, then you need to set up either Apache2 or an "svnserve" server. If you want Web DAV and all the other "goodies" that come with the Apache server, then yes, you'll need Apache 2.0.For more details about setting up a network accessible Subversion server, see chapter 6 in the Subversion book. It's always an option to run Apache 2.0 on a different port while continuing to run Apache 1.x on port 80.
Also, the revision number should not be used as the publicly-visible release number of a particular project in the repository.
Server requirements depend on many factors, such as number of users, frequency of commits and other server related operations, repository size, and the load generated by custom repository hooks.
When using Apache, it is likely that Apache itself will be the biggest factor in memory usage.
Most other projects probably would have called the product "1.0" much earlier, but we deliberately decided to delay that label as long as possible. Such limitations are always documented in the release notes of our releases.
We were aware that many people were waiting for a 1.0 before using Subversion, and had very specific expectations about the meaning of that label. The client and server are designed to work as long as they aren't more than one major release version apart. Our client/server interoperability policy is documented in the "Compatibility" section of the Subversion Community Guide.
Different versions of Apache can happily coexist on the same machine.