Back in the 802.11b days - 10mpbs - I was living in a place where there was no Web access whatsoever, by the shore, in a remote location. A closed village. And I found an ISP willing to provide me with access, even if it was wireless.
That ISP owner was a sort of rogue entrepeneur (the best sort), and since there were very few Federal Regulations whatsoever for that matter, we went for line-of-sight antennas - nearly parabolic dishes - installed on my rooftop, and a cell tower where he could rent a spot and had a fiber line. All major cell companies were using that tower, and they didn't give him two cents when he said he was using 2.4GHz.
We cranked those suckers well beyond any legal limits for testing. We managed to blackout the entire city BEHIND me - 20km away. NOT A SINGLE WIFI signal would work. The local FCC gave him a call, (in 72h), to remind him of the maximum power such transmitters could have.
In the end we settled - what were the values again? - in a transmitter with a couple of Watts of power over 20dBi antennas (is that the unit?) and managed stable 300kbps over 3 miles. Anything more powerful would reflect from the OCEAN next to me.
Three miles. He even ran some tests with PRINGLE CANS. In the end, I could run it nicely, and get wifi on the entire shore line, due to another omnidirectional antenna he put up. Once he developed it for me, he started selling to all my neighbours, and got a fantastic return of investment.
He kept that service for at least 10 years, until the large telcos/ISPs had any interest in the area.
Once we were inside legal power limits, we kept running that setup for quite a while unhindered, until we could grab 802.11g cards meant for PCMCIA sockets jerry-rigged into PCI boards by D-Link themselves... and the rest is history.
And not a single headache beyond the hassle of setting those suckers up on the roof, like they were TV antennas, and finicky pigtail sockets/connectors, and extra-thick one-inch RF cabling. drilled through a 20" wall.