For those of us in the (ahem) discerning minority the Mac equivalent is
Mac The Scope. Bit pricey but when I finally build my "ultimate" speakers and/or listening room it might be worth it.
For both platforms, and presumably Linux and Unix, there are less full-featured but useful shareware programs out there, too. (Hey, do we have any hardcore *nix geeks here? Just curious.)
Windows analysis software can of course run on Macs with VirtualPC, but judging from the few shareware demos I've tried you lose the full-duplex functionality of your soundcard, so generally you can't use the audio generator features; you need test CDs.