I'm reviving this thread, because I will be releasing the newest version of my site soon, and I would like suggestions before I upload my new version.
I've built a completely new template, added many mods from users here, and created many of my own mods. Almost every core file has been edited for this. Here a list of what my new version has so far.
Entire site properly skinned with dark and light versions, 8 color various for each version, and 13 background styles. User can easily select which appearance he likes best.
Complete Facebook integration, thanks to budduke
Jquery show categories based on the first letter, animated
Jquery sort wallpapers on category page by color, animated
Reply to comments, and threaded comments
User avatars, thanks to v@no
If user has Facebbok connected, he can choose to use his Facebook profile image as his avatar instead.
Use favorites/lightbox as a screensaver, with full settings panel. My own mod, not the old KurtW version
Edit the order of images in favorites/lightbox(also changes the screensaver order). I hope to make it drag and drop soon.
Fancy user profiles, like on social media sites. Shows users latest comments, uploads, favorites, visitor messages, and more.
User can click button to make all his profile items editable, right on his profile page(a.k.a. inline editing or wysiwyg editing)
Admin can click button on details page to edit all fields directly on the page, no need to go to the admin panel.
Search images by resolution/dimension, color, and more.
Ticket system(I forget who made it) to allow users to report images/users, to apply for ad space, or become affiliates
Various other things that I can't remember right now.
I'm also working on a custom news system. I don't like the ones available in the forums.
So my question is, does anyone have any other suggestions? I want to do as much as I can before I release the new version to my users. You can take a look at the current version of the site for ideas, but just remember that much of what you see there has already been rebuilt, and will look very different when I'm done.