I just got me a nice and shiny Linksys WRT610N — it was about time to upgrade the network, get a bit of a speed boost. Installation was trivial (no, you don’t have to insert a CD if you know what you’re doing), but for some reason I could not get my Macbook (unibody 17″, early 2009) to see “N” network, only “G” was visible.
Solution was simple, but took some searching. In “Basic Wireless Settings” under “5GHz Wireless Settings” set “Wide Channel” from “Auto (DSF)” to any specific value (I chose “46,” being a close enough match for 42).