I installed it and TF2. I've never played it before, I've always played the HL games (like Counter-Strike). So far I've only played the practice round! Can't wait to get some time to put it to the test.
What Distro are you playing on? I'm playing on Mint KDE 64 bit.
From what I hear Linus used to go with Gnome but when Gnome 3 was released he did not like it and he also did not like KDE so he went with XFCE. I tried that desktop with Virtual Box with xubuntu and did not like the lack of right-click menu's.