I had held off so long on upgrading to wireless N because it meant not only upgrading routers and access points, but it also meant you couldn't have any legacy wireless stuff hanging around to degrade the performance. Well, finally I wound up with only one stray wireless G adapter and I upgraded everything. My gaming PC, which was wasting my 75mbps FiOS by downloading at 20mbps is now getting a much more respectable 40mbps or so. Of course, new technology comes with new problems, and I had to do lots of fiddling with broadcast channels and stuff to get everything working at full capacity. Also found out that most wireless cards only support 150mbps even though my AP supports 300mbps.
Just in time for them to start coming out with wireless ac stuff, I'm sure. And who knows what all these waves bouncing around are doing to us. But downloads are faster, so who cares