Everybody's got a gimmick. Blogging Pro has themes organized by release date with thumbnail previews. How to Blog has over 170 themes organized by title. And, Shadow has themes organized by title with "a huge list of themes in use on site."
If you notice one thing in common about those three lists, it's that they all have something to bring to the table. If you want thumbnail previews, go to Blogging Pro's list. If you want possibly the largest and most comprehensive WordPress themes list, go to How to Blog's list. And, if you want to see live demos, go to Shadow's list. Well, it's about time our own list brought something to the table. I present to you the new Codex Theme List, now organized by column count.
Please keep in mind that we are all volunteers here. Personally, I do my best to keep the Codex list up to date, but I do miss some themes. The Codex is a community effort. If your theme is not listed on the Codex list, you can always add it yourself. The same goes for making URL changes (if your site moves, for example). You can add your theme to the other lists by notifying their authors.