2. There Are Lots Of Custom Maps Available
Back in May Valve released the "Perpetual Testing Initiative" which allows players to create new chambers with a user friendly level editor. A month later there were over 150,000 levels created and growing. These chambers run the gamut from intuitively simple to mind bendingly complex. At first the user created chambers were only for single players, but in August a patch was added that allows for co-op chambers to be designed. This means that avid players won't ever have to worry about running out of new levels to play, at least on the computer version. Xbox 360 and PS3 players are still waiting for new chambers to arrive and due to technical limitations won't be able to create levels of their own. So when they are able to play new chambers, the TV & Controller crowd will still be missing out on the greatest benefit of having a PC or Mac...