WiMax has been pushed hard for a while now by Intel and, as a consequence, is increasingly showing up in laptops. The idea is great: If WiFi is there, you use a really fast connection, in all other cases, you still have the fairly fast WiMax. Even the name sugggests that WiMax is a complement to WiFi. Of course, it has a competitor---the cell phone networks: HSPA is not as fast as WiFi, but it is much more widely deployed.
I haven't used either of these technologies, yet, so I don't know they compare. As an update on this competition, I've just read that one company that is currently deploying WiMax calls it a "miserable failure".