In case there are some Mac users here (hope I'm not the only one ^^), the wonderful Boxer app let you play Duke on Mac very easily. Boxer use DosBox (which is also available for Mac) but create instant packages of DOS games in a very easy way:
- download Boxer here -> http://boxerapp.com/
- install it
- a new window appears (the DOS Games folder created by the app, generally in "username"/ )
- drag and drop your game (original CD or game folder, or the GOG Duke Nukem folder in this case) on the " Drop games here to install them " icon
- your new Duke Nukem instant package is created, just double-click on it and before play, choose setup.exe
- my advice: choose "general MIDI" for music (Mac MIDI is far far far better than the Windows MIDI, the music just sounds incredible ^^)
- once all the setup is configured correctly, re-launch the Duke package, choose duke3d.exe and "launch forever", in this way, next times you'll play you will just have to launch the package without choosing a file (in case you need to use again the setup after choosing the "launch forever" option, just right-clic on the package and choose "show package content").
That's it! You can play GOG Duke on your Mac, without using Windows (except for the install of the game). Oh, and you can also play Duke Nukem Mac, if you have an old Mac... ^^

Nice.
I personally don´t have a Mac but it is really nice.
Sticky?

Can you compile eduke32 on a Mac? That's how I play it on Linux.

There's a build of eduke32 on OS X. I haven't tried it out yet. I assume that Duke3D from here will work fine with it.
http://www.spam-filter.de/osx/eduke32_on_os_x
The GOG.com installers also work perfectly using WINE, so you can use that to get the data files without access to Windows.