How many machines are you talking about and where are they located relative to each other? Does best mean "cheapest" or highest quality? Is high speed file transfers between the machines a top priority or do you just want to share internet?
My general advice is to hook up as many machines as possible via ethernet (e.g. use a router to connect machines in the same room) and use wireless as necessary for the rest.
Practicallynetworked.com has lots of reviews of wireless devices, including reviews submitted by users. I find it pretty helpful sometimes.