we have an airport extreme running in 11n + b/g compat mode, WPA-PSK, and it works fine with my n800 os2008, a colleague's n800 os2007 and my old n770.

that said, we've found our AE to be unstable and regularly needs power cycling, but that might be because there's loads of wireless lans around *and* there's a bunch of hairy techy people on the floor above who are probably trying to hack into our network!