For those of you who wish not to read this entire article...
Wi-Fi's real weakness is bandwidth-not its maximum capacity of 11Mbits/sec (really only 6Mbits/sec after protocol overhead is subtracted, which is still relatively high), but the limited amount of radio spectrum in which it operates.
-which is something everyone who knows anything about WiFi knows, especially when setting up several networks in close proximity.
Another quote at the end of the article...
But if you're planning a large deployment, and especially if you want to challenge the cellular operators in the wide area, go for 802.11a.
-Hmmmmm..... looks like there may be a big blowout sale on 802.11b hardware...
...can't wait!