The choice of desktop environment is quite a personal matter. I would recommend Gnome 3, which is especially polished on Fedora.
The early transition years from Gnome 2 to Gnome 3 were rough, and I switched to KDE for this time. KDE was fine, but Gnome 3 has been polished a lot in the last view years. So I switched back to Gnome 3 and never looked back :).
The early transition years from Gnome 2 to Gnome 3 were rough, and I switched to KDE for this time. KDE was fine, but Gnome 3 has been polished a lot in the last view years. So I switched back to Gnome 3 and never looked back :).