This year at PAX, nearly everywhere you looked you could find a PC game. If I had to choose which platform had the most diversity on the exhibition floor, I think it would be PC. Also, If I had to choose which platform had the longest lines and the biggest games, I think it would also be PC. Especially, the Blizzard booth.
Thankfully, each kiosk had two screens: one raised high enough for everyone to see, and another at the player level. All the Starcraft II kiosks were linked together, and everyone battled against each other.
There's not really much to say about Starcraft II though. It's... Starcraft II. Starcraft with updated graphics and game control. It's looks super pretty, too.
Of course, games of Starcraft II take a little time to play through, so that made the lines grow and grow. They started installing Starcraft II on some of the Lich King kiosks so everyone could play. Hahah. ^_^
I'm not really sure why you'd really want World of Warcraft: Wraith of the Lich King on a playable kiosk, anyways. All you'd really want to show off is the Death Knight and some of the new areas. For a little while, I watched one guy play and he was a Gnome Warrior running around... What a waste of time. They did have some demonstrations of Lich King, though, so it wasn't all a waste.