Nine Inch Nails:
Nine Inch Nails - The official site includes exclusive video clips, sounds, pics and more
Painful Convictions - Probably the best NIN fan site. Very comprehensive
Smashed Up Sanity - RIP - It may be gone, but the other sites on the network remain.
Nine Inch Nails Net - Downloads, Seems Like Salvation news, a forum and more
Rusty Nails - Great site, has everything, especially good for tabs
Absence of Faith - Large fan site with a useful NIN encyclopedia
Burning Souls - Nice layout, good content, videos, lyrics, etc
The Perfect Drug - Very nice site, original content, and a great design
Denial, Guilt and Fear - Cool fan site with lots of original content.
Check out the two fan sites above for more on Trent. There aren't many "Trent" pages per se, rather NIN sites, which is one reason I made this site.
For a more light-hearted and odd site on Trent, try The Official Anti Facial Hair on Trent page
Allison's Picture Page - Mad 'stalker' who took pics of Trent's house and other pics
Chris Vrenna - It's been a while, but he's still a cool musician
So You've Decided To Be Evil - A step-by-step guide to joining the Forces of Darkness, not some Satan Worshipping page but an amusing look at the clichés of good and evil. Just take a look and you'll see what I mean.
Marilyn Manson - The official Marilyn Manson page.
The Sampling Zone - With the help from this site, you could become the next Trent Reznor! Unlikely - yes, but it's still interesting and worth a look if you're interested in making music
Nothing Records - Finally, the much anticipated (and delayed) site opens.
Object Merchandise - Check out for loads of band stuff.