Then you've got a wireless network that you have to secure and manage. Welcome to the world of 802.1X, rogue access points, wardriving. Say goodbye to the world of switched Ethernet with dedicated bandwidth per end user and welcome to the world of shared bandwidth among users who are moving all over the place, all expecting to be able to download the same-sized files and watch the same video as they did before.
Is 802.11n an exciting new technology? Definitely. Should I be trying it out? By all means. But be aware that an enterprise deployment is a huge deal that will require serious upfront planning.