Using a simple 3db omnidirectional antenna under UK rf emissions guidelines (100mW) I have achieved 5.5Mb rates using Symbol and Cisco Aironet 802.11b kit at 8 kilometres.
With a standard Huber Suhner (can't remember spelling) antenna I have pushed this up to 14 kilometres.

I was hoping to set up direct link to a friend who has a 2Mb pipe, but ended up moving house instead

In the USA you can up the output power to 1W in most areas, so you get even better range. Lucky [censored]