I run a very popular site dedicated to strange photos...right now it functions mainly as an archive but I would like to make the transition to a 'photo of the day' type of blog.

The biggest thing I need is the ability to create categories for each entry, i.e. animal photos, sports photos, etc., and have each category list the entires in an easy to read list. An easy to implement mod_rewrite for search engine friendly URLs and RSS are absolute musts. An easy-to-modify template system is preferred. The ability for users to leave comments would be nice.

A free blog is preferred, but I don't mind paying if it has all the right features and I can test drive it first.

I've looked around and haven't found anything that fits my criteria. It is very possible that I just don't know how to search for what I want.

Any suggestions would be most welcome.