Starting with those open source packages, Fedora 11 comes with KDE 4.2, GNOME 2.26, Xfce 4.6, Xserver 1.6, Firefox 3.5, Thunderbird 3, Python 2.6, GCC 4.4 (all packages have been rebuilt with GCC 4.4 as well), and much more. Obviously, Fedora 11 also inherits all the improvements made in those projects.
There's also a lot of other cool stuff in Fedora 11. For instance, ext4 is now the default file system for Anaconda-driven installs, which would mean speed improvements for Fedora users. The boot time target is now 20 seconds (it was 30 seconds for Fedora 10), which really puts into perspective just how much the Linux desktop has improved in this area over the past couple of years.
The Nouveau driver for NVIDIA graphics chips is now the default in Fedora 11, and with it comes kernel modesetting support for this driver. Improvements have also been made in the areas of DRI2, DeviceKit integration, support for fingerprint readers, PolicyKit integration with CUPS, and a whole lot more.
Fedora 11 is not yet released to the mirrors, so I don't have a download link for you just yet. It will be released later today.