I will buy it on release day (hell, if there's a collectors edition I will get that too). I remember playing DN3D on a Pentium 133Mhz machine running Windows 95. During the era of Doom clones Duke Nukem stood out by featuring vertical aiming, dynamic environments (earthquakes, environmental explosions, etc), carried items, interactive objects, jetpacks, and character. Plus the whole game was a huge parody. From what I've seen of the demo it looks like DNF will keep with this tradition.
tl:dr DN3D was a revolutionary game for its time and DNF is shaping up to be a worthy successor.