I consider the inclusion of ipset to be a big deal. It certainly makes things easier and faster for people who do whitelisting, or have large block lists on servers. There are many times I've thought "I sure wouldn't mind using ipset here" only to decide it wasn't worth it due to the pain of compiling it myself and getting it to work with any given distro. Now that it is stock-kernel, the pain goes away. I'd expect to see it start cropping up in all sorts of places (e.g. torrent block lists)