Also, there's a "High-Resolution Pack" that is legally downloadable for free to update the graphics for Duke Nukem 3D for the PC. All you need is any of the versions of Duke Nukem 3D in your PC and click on the fallowing sites to download the HRP, mods, and more from 3D Realms's site.
http://hrp.duke4.net/
http://www.3drealms.com/
I grew up with Duke Nukem 3D since I first played it on the N64 at age-6 and still it hasn't lost its appeal for me. I still keep Duke Nukem in my heart and enjoyed the hell out of the series. I've been waiting for Duke Nukem Forever for a very long time and I'm more than excited to play this game and FINALLY playing something original in FPS.