Subversion is always a great choice for source control, and in the summer it looks like there will be an update to version 1.5 with some fairly major features.
The most important of these features is the merge tracking which is detailed in this blog post. It is not a problem for a simple life of development, but when you are maintaining multiple branches with multiple requirements and they all need to know what revisions have an haven't been merged you really need to know what is going on. With Subversion up until the upcoming 1.5 you would just have to be conscientious and meticulous.
There is a list of all issue reports that are targeted for Subversion 1.5.
Also for Subversion resources there is a great blog here which has more about what the developers are planning (or would like to ideally include). You can see the Subversion roadmap here. There is also an issue list for what could be potentially included in 2.0. Oh and finally the plans for TortoiseSVN in relation to Subversion 1.5.
Edit: Thanks to hwright for the comment that Planet Subversion is an aggregator for Subversion blogs. Cheers!